New Baton Rouge flood map show limits of current risk and planning methods

This aerial image shows flooded areas of North Baton Rouge, La., Saturday, Aug. 13, 2016. Louisiana Gov. John Bel Edwards says more than 1,000 people in south Louisiana have been rescued from homes, vehicles and even clinging to trees as a slow-moving storm hammers the state with flooding. (Patrick Dennis/The Advocate via AP)

This aerial image shows flooded areas of North Baton Rouge, La., Saturday, Aug. 13, 2016. (Patrick Dennis/The Advocate via AP)

by Nicholas Pinter, Nicholas Santos, Rui Hui, Kathleen Schaefer

The flooding in Baton Rouge and surrounding areas of Louisiana is a major disaster, claiming an estimated 13 lives and displacing more than 100,000 people from their homes. The National Weather Service reported that rainfall in Louisiana this past week reached up to a 1000-year event (0.1% chance of occurring each year). The American Red Cross has called this the worst US disaster since Hurricane Sandy.

Our team of researchers in the Natural Hazards Research and Mitigation Group at the University of California, Davis undertook a preliminary analysis to determine extent of flood inundation during this recent event and its relationship with Louisiana’s history of major floods and development behind levees.

Louisiana has a long history
BatonRougefloodfactsof disastrous flooding. In 1998, the National Wildlife Federation report Higher Ground ranked two of the parishes hard-hit by this week’s flooding, East Baton Rouge and St. Tammany Parish, 7th and 22nd among communities nationwide with the highest damages for repetitive-loss properties.  In 1998, there were 1,107 repetitive loss properties in these two parishes, resulting in claims to the NFIP totaling $47,534,736.  As of November 30, 2015, these two parishes were still in the top 25 severe repetitive loss properties (22nd and 5th respectively for payments received); NFIP claims total $117,131,310.

The National Flood Insurance Program (NFIP) was established in 1968 to curtail flood damages through nationwide mapping of flood hazard to guide sound floodplain management.  NFIP maps (“FIRMs”) are used to inform residents of potentially flood-prone land, guide development and construction ordinances, and to set insurance rates and requirements.  We analyzed the distribution of flood inundation around Baton Rouge in order to assess how well NFIP and FEMA maps provided guidance to avoid damages during the extreme and, arguably, unusual precipitation and flooding this past week.

One-third of the flooding we mapped was outside of FEMA’s designated 100-year flood zone, which is the “line in the sand” for floodplain management in the US.  Many floodplain residents and political leaders falsely believe that flooding cannot occur beyond the mapped 100-year line.  But nationwide, roughly 25% of NFIP flood-damage claims occur outside of 100-year zones.  This can result from drainage problems (as opposed to rivers going over their banks), because of levee failures, where local FEMA map panels are out of date, because climate change or basin development have worsened flooding, or simply because an area gets hit by an event larger the so-called 100-year storm (1% annual probability).  For all of these reasons, flood insurance can be a great deal and is highly recommended in many areas outside of FEMA mapped hazard areas, as events in Louisiana show.

Analysis of NFIP Policies and Past Claims in the Flooded Area

We obtained databases of NFIP policies back to 1994 and insurance claims nationwide back to 1972.  For the analysis here, we identified current policies and past claims for 19 communities in the flooded area near Baton Rouge that are part of the current Louisiana Presidential Disaster Declaration, e.g. communities in East Baton Rouge Parish and Livingston Parish. As of June 30, 2016, these communities have 54,644 NFIP policies-in-force covering around $12 billion in property, with those policy-holders paying about $40 million in annual premiums. The number of NFIP policies in these communities increased regularly from 1994 to 2014 (Figure 1), with a sharp increase following Hurricane Katrina in 2005.  The largest portion of this increase was for properties outside the mapped 100-year floodplain – property owners who bet wisely and are now facing a much more secure future than most of their neighbors.

BatonRougeimage

Figure 1. Annual number of policies in force from 1974 to 2014, by flood zones

Like all of Louisiana, the area hit by last week’s storm has a long history of flooding. From 1972 to early 2015, the communities we studied as part of our analysis had 16,403 paid NFIP claims. Of these, 10,961 claims (67%) were for properties located in 100-yr floodplain, 2,811 (17%) for properties out of 100-yr floodplain, 74 (0.5%) in coastal hazard area, and the remaining 2,577 claims (16%) were in undefined areas (Figure 2). The total building and content damages for these claims are about $422 million in 2016 dollars, which includes $293 million for properties located in 100-yr floodplain, $76 million outside of 100-yr floodplains, about $3 million in coastal hazard areas, and $49 million for properties located in undefined areas (Figure 3).

FloodingFig2

Figure 2. Annual number of NFIP claims paid from 1972 to 2014, by flood zones

FloodingFig3

Figure 3. Annual building and content claim payment in 2016 dollars, by flood zone

Satellite-Based Flood Inundation Analysis

Using imagery from the European Space Agency’s Sentinel-2A satellite in the vicinity of Baton Rouge, Louisiana, we mapped flooding from the recent storm event (Figure 4).  While much of the area was still obscured by clouds on Aug. 14, East Baton Rouge and nearby communities were mostly clear.  About 30 square miles of flooded surface were mapped in the Baton Rouge area, which does not include additional flooding inside of buildings or in cloud-obscured locations. This flood inundation was overlain on FEMA’s National Flood Hazard Layer, which shows floodplains as identified on Flood Insurance Rate Maps, as well as the National Levee Database (NLD).

About two-thirds (66 percent) of the flooding detected from satellite imagery in the study area occurred inside of FEMA’s Special Flood Hazard Area (SFHA; Zones A and AE in Table 1), which is the regulatory standard in the US.  The SFHA aims to identify areas that would be inundated by the so-called 100-year flood event, meaning the flood that has a 1% chance or less of occurring in any given year.  Some FEMA maps also identify areas subject to larger 500-year floods (0.2% chance in any given year), and these areas around Baton Rouge also experienced extensive flood damages.  This is expected during such an extreme storm event, and serves as a reminder to residents and local leaders to remember flood hazard during the many years and even decades where mapped floodplain land may remain dry.  Even more importantly, flooding above the 100-year level is a harsh reminder to all of us – a rebuke to the US system in which development and construction can in many cases occur mere inches outside of the 100-year line.   

BatonRougetable

Table 1. Distribution of flood inundation in the study area around Baton Rouge, LA in different mapped flood zones

The US Army Corps of Engineers National Levee Database (NLD) provides levee protection information for about 14% of the estimated 100,000 miles of levees in the United States.  We identified 147 mi2 of levee-protected area in our study area around Baton Rouge, but the majority of that area is west of the Mississippi River. Most of the studied area east of the Mississippi River lacked levees or else has levees that are not included in the NLD.

News reports from Louisiana include reports of breaches or overtopping of several levees by flood waters and in our analysis, we identified 11.5 square miles of flooding within levee-protected areas, mostly in East Baton Rouge. A well-known limitation in US flood-risk policy is that land behind levees certified and accredited as able to withstand 100-year or larger floods is written out of flood-hazard maps, but levees do not reduce flood risk completely. Residents and business owners behind any levee should look to Louisiana and remember that every levee carries a “residual risk” of failure or overtopping during an extreme event.  In some cases, levees even create their own flood risk, when drainage systems and pumps are overwhelmed by locally intense rainfall.  FEMA does not map for such “drainage flood”, and early reports indicate that this type of flooding was prevalent during this event in Baton Rouge.

Conclusion

There are numerous lessons to be learned from the recent flooding in Louisiana.  As evacuations and rescues turn towards flood recovery, careful research should target the distribution of flooding and flood damages.  In particular, the extent of inundation outside of mapped hazard zones should be studied in order to guide both recovery and future planning efforts.  Inundation outside of FEMA’s SFHA, or 100-year floodplains, may be attributed to the extreme intensity of this weather event.  But every 100-year or larger flood is an extreme event, and such “Act of God” explanations are too often used as an easy out that can serve to dodge systematic assessment of past planning and flood-risk enforcement and development.  Widespread flooding outside of mapped hazard zones can also reflect climate-driven shifts, land-surface changes that generate larger storm runoff, stream-channel modifications, overreliance on levees, or outdated maps (sometimes willfully delayed by local development interests).

In addition, our experience working with flood-impacted communities across the US and worldwide highlights that decisions made in Louisiana during the next few weeks can determine the region’s long-term future.  Key decisions will be made on whether to clean out the mud and rebuild in place or, instead, whether to mitigate – invest now in reducing future flood losses.  Homes can be elevated or flood-proofed, and the most flood-prone properties can be relocated to safer locations.  Research shows that each $1 invested in flood mitigation in the US returns an average of $4-5 in long-term savings.  And our experience is that the first weeks following a major flood disaster are a window of opportunity that soon closes.  Louisiana residents, disaster managers, and political leaders need to take a step back and look at the regional pattern of flood damages in this event and back through time.  Now is the opportunity to step off the path of repeated flood losses and instead make decisions that will move the region and its residents towards a more resilient future.

Author bios: Nicholas Pinter is the Roy Shlemon Professor of Applied Geosciences in the Department of Earth and Planetary Sciences and an affiliate of the UC Davis Center for Watershed Sciences. Nick Santos is a GIS developer and researcher at the Center for Watershed Sciences. Rui Hui is a postdoctoral researcher with the Center for Watershed Sciences. Kathleen Shaefer is a prospective graduate student at UC Davis, and previously worked as a Regional Engineer for flood projects with FEMA Region IX.

Further reading

National Wildlife Federation, Higher Ground: A Report on Voluntary Property Buyouts in the Nation’s Floodplains. Washington, D.C., July, 1998

NFIP Loss Statistics from Jan 1, 1978 through June 30, 2016.  http://bsa.nfipstat.fema.gov/reports/1040.htm#22 accessed on 8/17/2016.

Map of Baton Rouge Flooding as of August 14th, 2016. https://watershed.ucdavis.edu/experiments/baton_rouge_2016/map

Posted in Planning and Management, Uncategorized | Tagged , , , , , | 4 Comments

Scott Valley pioneers instream flow and groundwater management for reconciled water use

by Gus Tolley

ScottRiver

Scott River at Horn Lane, November 2013. Photo credit: Sari Sommarstrom.

The Scott River is one of California’s four major undammed streams and important spawning habitat for coho (a species listed as “threatened”) and Chinook salmon. This peaceful and pastoral agricultural valley is at the center of several water-related conflicts and lawsuits. However, it is also pioneering a range of instream flow and groundwater management activities that could set the example for balanced water use in California.

At first glance, water ScottValleyHLUmanagement in the Scott Valley appears to be a story of farms vs fish, one that is common in California: A dry year results in dry stream reaches near groundwater-irrigated fields in August that persist beyond the irrigation season into September, even October. With the Chinook fall spawning migration arriving in mid-October and coho following soon after, a dry streambed raises valid concerns about how irrigation pumping and the removal of riparian vegetation may have led to warmer and drier streamflow patterns in Scott Valley.

The story behind the valley’s seasonally dry streams is complex. Irrigated pasture, alfalfa, and cattle production have been part of the socioeconomic fabric since it was settled by white people during the mid 1800s. Current dry conditions are partly due to legacy impacts from historical land management policies, flood control, and gold mining, along with natural climatic and geologic variations.

irrigationOn average, the annual discharge of the Scott River is more than five times the total evapotranspiration demand from the 34,000 irrigated acres in the valley; seemingly enough water for fish and farming.  But – like elsewhere in California – surface water supplies usually dry up around July when the last of the snowmelt in the upper watershed disappears. Streamflow from mid-summer until the beginning of the rainy season largely depends on baseflow from the valley aquifer. Fed by recharge from tributaries, rainfall, and excess irrigation, the aquifer acts as a large, sponge-like reservoir that provides a steady contribution to streamflow in the summer and early fall.

In the 1970s, average late-summer streamflow in the Scott River decreased markedly by about 50%, resulting in increased stream temperatures and – during dry years – more pronounced dry stream reaches along the lower valley floor. How did the Scott River get to the condition it is in today?

Figure 1: Late summer streamflow in the Scott River has decreased significantly since the 1970s.

Figure 1: Late summer streamflow in the Scott River has decreased significantly since the 1970s.

A driving factor for the change in average summer flows may be a switch from reliance on surface-water prior to the 1970s to a greater use of groundwater for irrigation. Following the 1977 drought, many farmers moved from using surface water for flood irrigation to pumping groundwater. Groundwater is more reliable and the preferred source for more efficient irrigation methods such as wheel lines and center-pivots that are encouraged by agencies like the National Resource Conservation Service (NRCS). Access to groundwater allows for irrigation after surface water supplies are no longer available, but pumping groundwater reduces discharge from the aquifer to the stream.

Changing sources of irrigation water has had several major impacts in the valley, including:

  1. decreased groundwater recharge in the spring and summer due to increased irrigation efficiency,
  2. increased groundwater pumping, and
  3. net increase in consumptive crop water use (evapotranspiration) due to the ability to irrigate alfalfa into August or September for a third or fourth cutting instead of two cuttings through July.

Notably, with water supplies greatly exceeding water demand, there is no evidence of long-term groundwater overdraft in the Scott Valley. However, pumping near the Scott River seasonally lowers groundwater levels sufficiently to impact streamflow during the late summer, especially during the critical time between the end of the irrigation season and the beginning of the rainy season when Chinook and coho start their fall spawning runs.

Valley residents have been proactive ScottValleyin finding solutions to the problem of decreased late-summer streamflow. The Scott River Water Trust, the first active water trust in California, leases water from farmers with the goal of improving streamflow for salmon and steelhead at critical points during their lifecycle. The Scott Valley Groundwater Advisory Committee was established, which assists with data collection and monitoring, provides information about local farming practices, and suggests potential methods for increasing late-summer streamflow in the Scott River. Additionally, a Community Water Level Measuring Program has been monitoring about 34 wells monthly since 2006. UC Davis professor Thomas Harter and his research group have used this information to develop an integrated groundwater-surface water model of the Scott Valley that can test different management options for increasing late-summer streamflow.

One proposed solution for groundwater recharge is flooding dormant agricultural fields during the winter when streamflow is high and water is available. In January 2016, the Scott Valley received the first temporary groundwater storage permit issued in California to test this option. The goals of the groundwater recharge project, headed by UC Davis professor Helen Dahlke, are to quantify how much water can be recharged on agricultural fields, determine potential negative effects on the crop, and identify best management practices in the hopes this method can be applied to other areas in California as well.

flowdifference3Another management option is the conjunctive use of surface-water and groundwater involving a dual-irrigation system where more surface-water is used while it is available during the spring months to reduce groundwater pumping. Although this would require an investment in infrastructure and coordination among stakeholders, preliminary modeling results show promising streamflow increases when this management scenario is implemented.

Work will continue to improve fish habitat quality and quantity in the Scott Valley while also maintaining agriculture. There is no magic bullet, and the path forward will rely on a portfolio of management solutions, supported by active stakeholder engagement, monitoring, assessment, and modeling. Some actions may be achieved relatively easily, while others will require coordination and cooperation among stakeholders with some significant investments to successfully implement.

Gus Tolley is a doctoral candidate in the Hydrologic Sciences Graduate Group at UC Davis and 2015 UC President’s Global Food Initiative fellow. His work focuses on numerical modeling of interactions between groundwater and surface water in agricultural areas.

Further Reading

Barlow, P.M., and Leake, S.A., 2012, Streamflow Depletion by Wells — Understanding and Managing the Effects of Groundwater Pumping on Streamflow, USGS Circular 1376

Fleckenstein, J.H., Niswonger, R.G., and Fogg, G.E., 2006, River-Aquifer Interactions, Geologic Heterogeneity, and Low-Flow Management: Ground Water, v. 44, p. 837–852, doi: 10.1111/j.1745-6584.2006.00190.x.

Foglia, L., McNally, A., and Harter, T., 2013, Coupling a spatiotemporally distributed soil water budget with stream-depletion functions to inform stakeholder-driven management of groundwater-dependent ecosystems: Water Resources Research, v. 49, no. 11, p. 7292–7310, doi: 10.1002/wrcr.20555.

Hall, M., Harter, T., and Frank, R., Groundwater problems and prospects, part 7: Groundwater-dependent ecosystems and the groundwater-surface water connection, Maven’s Notebook.

Hoben, M. L., 1999, Scott River Coordinated Resource Management Council, in Systematic Assessment of Collaborative Resource Management Partnerships [Master’s Thesis], University of Michigan, 357 p.

Kendy, E., and Bredehoeft, J.D., 2006, Transient effects of groundwater pumping and surface-water-irrigation returns on streamflow: Water Resources Research, v. 42, no. 8, p. n/a–n/a, doi: 10.1029/2005WR004792.

Website for Professor Dahlke’s Research Group

Website for Professor Harter’s Research Group

Posted in California Water, Groundwater, Planning and Management, Salmon, Uncategorized, Water Markets | Tagged | 4 Comments

Economic Analysis of the 2016 California Drought for Agriculture

by Josué Medellín-Azuara, Duncan MacEwan, Richard E. Howitt, Daniel A. Sumner, and Jay R. Lund

The drought continues for California’s agriculture in 2016, but with much less severe and widespread impacts than in the two previous drought years, 2014 and 2015.  Winter and spring were wetter in the Sacramento Valley, to the extent of several reservoirs being required to spill water for flood control, but south of the Delta was unusually dry.  The much-heralded El Nino brought largely average precipitation north of the Delta, replenishing some groundwater, and drier than average conditions to the southern Central Valley and southern California.  The historical pattern of increasing water exports from the Sacramento-San Joaquin Delta in these circumstances was less available due to environmental restrictions on Delta pumping.  Some concerns also remain for water supplies north of the Delta regarding temperature releases from Shasta reservoir.  The overall estimated impacts of the 2016 drought on agriculture are summarized in the table below.

 Survey work on expected surface water deliveries to agricultural water districts, and public announcement from main water contractors indicate a surface water shortage of 2.6 million acre-foot of water for agriculture during the 2016 irrigation season mostly for the Central Valley. This is roughly 14 percent less than a normal statewide surface water supply for crops.  This shortage is reduced with nearly 1.9 million acre-foot of additional groundwater pumping for a net water shortage of 0.7 million acre foot or 2.6% of the estimated applied water in agriculture.

 With this water shortage, about 78,800 acres of land could be idled due to drought, a small proportion of California’s 9.3 million acres of irrigated crops. Almost all fallowed land due to drought is projected to be on the west side of the San Joaquin Basin which relies heavily on water imports. No significant drought related impacts are expected for livestock and dairies this year as this sector is more affected by market conditions than drought this year. Net water shortages will cost about $247 million dollars in forgone gross crop revenues plus $303 million in additional pumping costs for a total of $550 million in direct costs and 1,815 jobs lost in agriculture due to drought. Region-wide effects which include sectors supporting agriculture face gross revenue losses and households lost income of an estimated $603 million and 4,700 jobs statewide.

2016 ag drought table

Groundwater is responsible for offsetting about 70 percent of the statewide surface water shortage for agriculture. The energy cost of this additional pumping equals $300 million, exceeding estimated crop losses due to drought. The progressive depletion of groundwater during the drought also has increased costs for rehabilitation and replacement of domestic and agricultural wells.

 Environmental issues from fish stocks further weakened by earlier years of drought have left irrigation district managers concerned about the potential for late-season curtailments to manage reservoir water temperatures for fish habitat.  Delta environmental water operation constraints this year have prevented additional through-Delta water transfers, effectively shutting down the 2016 water market across the Delta.  Water transfers from the Sacramento Valley to the San Joaquin Valley helped offset some of the economic cost of the 2014 and 2015 drought.

 Pasture conditions and feed market conditions have improved for livestock producers, but low cattle and milk prices place intense economic pressure on producers.

 Groundwater reserves and national and global market conditions continue to support the health and robustness of areas of California’s agriculture still affected by water shortages. Modest recovery in contract labor growth from 2014 to 2015 is apparent from labor statistics due to favorable market conditions for California’s commodities. Water management in the Sacramento San Joaquin Delta for protecting endangered species and access to groundwater remain important for sustaining water supply for California’s agriculture and related sectors. A better accounting of water use and water reserves along with other management tools will facilitate groundwater management, water market transfers, and overall water management and policy for drought.

 These results were developed by this team of researchers from UC Davis Center for Watershed Sciences, ERA Economics and the UC Agricultural Issues Center for their third drought economic impact assessment on agriculture commissioned by the California Department of Food and Agriculture.

 Further Reading

Josué MedellínAzuara, Duncan MacEwan, Richard E. Howitt, Daniel A. Sumner, and Jay R. Lund (2016), Economic Analysis of the 2016 California Drought on Agriculture, A report for the California Department of Food and Agriculture, with research support from Jennifer Scheer, Robert Gailey, Quinn Hart, Nadya D. Alexander, Brad Arnold, Angela Kwon, Andrew Bell and William Li, Center for Watershed Sciences, University of California – Davis, August 11, 2016.

 

Posted in Agriculture, Drought, Uncategorized | Tagged , , , , | 11 Comments

Visualizing Flows – A Sandbox Experience with Modeling

by Jeanette Newmiller

In winter quarter 2016, Dr. Colleen Bronner of the UC Davis Department of Civil Engineering gathered a small group of graduate students and posed a challenge. To support new education standards involving teaching engineering methods throughout K-12 education, Dr. Bronner asked the graduate students design education outreach modules that reflected their research work in engineering. The modules should engage students in understanding the work of engineers while satisfying several Next Generation Science Standards and Common Core Math Standards. Ultimately, the modules needed to be accessible for K-12 teachers to use.

Challenge accepted.

As a graduate student with the UC Davis Center for Watershed Sciences, I’m producing a computer model of potential scenarios for passing water from the Sacramento River to Yolo Bypass in low flow conditions for winter run juvenile salmon access to beneficially flooded fields (see Nigiri Project). Most of the work is on a computer… using specialized software… that I run off a server with 64 processing cores… hmmm… kids… big computers… complex software… kids…

… I have a great job with a cool story about how engineering can help baby salmon eat more food, grow bigger, and have a better chance of survival once they hit the ocean. What I needed was a computer model accessible to kids. So bring on the Augmented Reality Sandbox developed by UC Davis researcher Oliver Kreylos.

The Augmented Reality (AR) Sandbox lets kids (ages 3 to 103) build a watershed model in real sand. A sensor monitors the changes in the sand’s shape, a computer processes the information, and a projector displays the computer model back onto the sand in the form of a digital elevation map (DEM) with a vibrant color gradient and contour lines. The model uses the Saint-Venant set of equations for shallow water to produce a realistic simulation of water flow over the landscape. The sand is essentially the input and output device for a fairly sophisticated surface water computer model – totally accessible to kids.

The existing AR Sandbox at the UC Davis KeckCAVES is big and it is heavy. Moving it almost requires a forklift. For use in classrooms it must be portable. I designed and built an AR Sandbox on a rack that allows it to be rolled though an ADA compliant door. It can be easily disassembled, packed into a car, and reassembled on site without tools. The Sandbox can be set up at different heights to accommodate kids of different ages or abilities.

The portable AR Sandbox and supporting activities were recently tested with a group of middle and high school teachers and a group of 3rd-5th grade girls. The sandbox was a hit, with excellent feedback to help develop curriculum which I plan to submit to the TeachEngineering digital library of K-12 curriculum.

As with all sand boxes, keeping the sand in the box remains a problem.

Another AR Sandbox will be on display in the Lobby of the Center for Watershed Sciences. Stay tuned…

Jeanette Newmiller is a graduate student in the UC Davis department of Civil and Environmental Engineering and student researcher at the UCD Center for Watershed Sciences. Her work focus on the development of surface water models for the integration of human and ecological needs.

The technology for the Augmented Reality Sandbox was developed by the LakeViz3D project – UC Davis KeckCAVES, UC Davis Tahoe Environmental Research Center, Lawrence Hall of Science, ECHO Lake Aquarium and Science Center, and Audience Viewpoints, and funded by the National Science Foundation. This portable exhibit was designed and constructed by Jeanette Newmiller with support from the NSF-funded Engineering Research Center for Bio-mediated and Bio-inspired Geotechnics (Award Number: 1449501).

Further Reading

Augmented Reality Turns a Sandbox into a Geoscience Lesson, EOS, 2016. https://eos.org/project-updates/augmented-reality-turns-a-sandbox-into-a-geoscience-lesson

 

 

Posted in education, Tools, Uncategorized, Virtual Water, Water System Modeling | Tagged | 4 Comments

Local groundwater management in France and California

by Corentin Girard

 

SAGEmap

Figure 1: Approved French SAGE in January 2016 (adapted from EauFrance, 2016b)

France and California have different environmental, agricultural, economic, institutional, and cultural contexts. However, both are moving to more local management of groundwater. In California, the 2014 Groundwater Sustainable Management Act required creation of  local Groundwater Sustainable Agencies (GSA) and Groundwater Sustainability Plans (GSP) to end groundwater overdraft and other undesirable conditions by 2040.

France has a similar water policy reform process. The 2006 French water law (JORF, 2006) shifted from centralized management of individual withdrawals to decentralized management of collective withdrawals. In both cases, local management of groundwater is intended to address the problems of un-regulated, unmanaged (California) or centralized (France) management of groundwater. Challenges in California have been discussed in previous posts. After a brief presentation of the French context, we compare these two approaches.

Historically, French legislation considered groundwater as “Res Nullius”, i.e., without owner, implying that groundwater could be used by private owners of overlying-land. Such private use occurred from the 1970s to 1980s with rapid development of individual groundwater irrigation, and very permissive regulation[1]. Successive droughts, technical improvements, and public subsidies favored development of groundwater for agricultural irrigation. Farmers without access to surface water or large collective irrigation systems started using groundwater to irrigate in regions historically without tradition of irrigation (in central and western France).

The 1992 French Water Law defined water resources as unique and recognized them as the “common heritage of the Nation”. The 1992 water law allows the creation of Local Water Committees (Comite Local de l’Eau, CLE) in charge of defining a local water resources management plan (Schema d’Amenagement et de Gestion de l’Eau, SAGE) through a negotiation process involving government agencies and selected members of local authorities, farmers’ representatives, water utilities, including associations for environmental protection and recreational activities. This local plan follows national and European water legislation, as well as the guidelines given by the river basin management master plan (Schéma Directeur d’Aménagement et de Gestion des Eaux, SDAGE) developed at the River Basin District level by the river basin authority (large watershed) (Figure 2 and Table 1).

SAGE

Table 1: Facts about French SAGE (Eaufrance, 2016a)

The 1992 water law introduced an administrative procedure of annual individual declaration/authorization to control water withdrawals. Administrative requirements increased with the quantity of withdrawals[2]. Groundwater withdrawals could be temporarily limited by the State when critical groundwater thresholds were reached. Users were required to meter and record their water withdrawals and the state could remove withdrawals permits without financial compensation.

FrenchWatermgmt

Figure 2: French water management organization

However, in practice the lack of financial and human resources for enforcement jeopardized capacity to control and enforce the law. In some regions, the number of individual extractions points was difficult or impossible to establish and monitor with an acceptable level of confidence. Previous water withdrawal authorizations were almost never reduced by the state. Finally, the use of groundwater level indicators did not always prevent over-abstraction and increased pumping for pre-irrigation. As a result, the groundwater level thresholds defined for crisis management in one year out of five were reached almost every year in many areas.

Learning from these difficulties, France’s 2006 water law requires a balance between withdrawals and available resources at the local level to ensure that supply of water uses and environmental objectives are achieved in four years out of five. In areas with structural quantitative deficit (Zone de Repartition des Eaux), a maximum Extractable Volume (maxEV) must be defined by the Local Water Committee composed of involved stakeholders (Commission Locale de l’Eau, CLE) or by the state authorities. In areas where groundwater use for irrigation is significant, farmers shall form a Water Users’s Association (in French: Organisme Unique de Gestion Collective, OUGC) that will limit withdrawals below their share of the maxEV. This sometimes required reductions of 10 % to 50% of existing withdrawals.

The OUGC will apply for a single administrative authorization less than the maximum extractable volume for up to 15 years. The single authorization replaces all previous individual ones in the area, and the OUGC will be legally responsible for allocating this volume to its members, while enforcement responsibility remains with the State

In exchange, the state transferred to the OUGC responsibility and freedom to define:

  • Governance structure of the OUGC
  • Financial contribution of members (up to 70% of operational cost covered by public subsidies)
  • Management of claims / conflicts among members
  • General allocation rules
  • Specific allocation rules during drought
  • Rules to decide how to integrate new comers

Farmers in an OUGC also will benefit from lower groundwater withdrawal fees, and can access funding and collect fees for the operation and maintenance of the OUGC.

Nevertheless, the implementation process faces farmers’ opposition. Some farmers perceive it as collectivizing  agriculture, feeling that they lose individual control over individual water entitlements which they perceived as “private property”, other perceive it as an easy way for the State to delegate its responsibility over the problem or worry about their legal responsibility as part of an OUGC (Figureau et al., 2012). The evaluation of “extractable” volumes is seen as riddled with uncertainties, and final pumping volumes are sometimes negotiated more on economic and political than environmental grounds (within the Local Water Committee). To facilitate implementation, the government provides some financial support for developing of small dams and reservoirs. Implementation is now making progress thanks to the support of local agricultural councils (Chambre d’Agriculture) taking the lead in running the OUGCs. Indeed, the OUGC is not a new institution and its responsibilities can be taken over by existing organizations as long as they are recognized by the farmers and the state administration. The local agricultural council centralizes the annual authorization and implements reductions when the sum of requested volumes exceeds the maxEV. The first OUGCs have been created, and often the local agricultural council volunteer to form the OUGC and the state representative (“prefet”) validates and formally designates them as the OUGC.

As in California with the creation of the Groundwater Sustainability Agencies, the process of developing collective institutions for groundwater management provides a wide range of options depending on the local resources, social and cultural context. The implementation will also clarify how the law must be interpreted, as until now many uncertainties remain.

The French 2006 water law, as with the 2014 SGMA in California, relies on collective management of groundwater as a mechanism to give flexibility in allocating scarce resources, while maintaining equity among users. However, some clear differences exist between local groundwater management in France and California (Table 2). In California, groundwater and surface water resources are still considered separately in governance and regulation, whereas French governance allows more direct integration of these resources. In both cases the new legislation expects the local institution to be able to limit the overexploitation of the groundwater. However, in the Californian case the prior right to access groundwater from overlying land for reasonable use is not directly modified by SGMA. In the French case, previous individual withdrawals authorization by the state are replaced by a single collective authorization that farmers will have to share.

French governance relies now on two steps to control agricultural groundwater withdrawals. First, objectives are defined among the different users, including the farmers. Then, the farmers have to organize themselves to achieve the negotiated objectives. In California, the farmers are not directly part of the GSA, even if some of their representatives in irrigation districts can be part of the GSA.

The role of the state is clearly different. In France, the State takes part in the negotiation process; in California, the State can support the negotiation process, but mainly controls its outcomes by evaluating and validating the GSA or the GSPs.

Performance indicators or guidelines for achieving objectives are not clearly defined in California’s SGMA, as the local GSA must define them. In the French case, the maxEV is clearly a requirement to achieve the objectives, even if the way it will be monitored will have to be defined at the local level as well.

Table 2: Comparison of local groundwater management in France and California (green =similarities, yellow=differences)

Criteria California (CA) France (FR) Comments
Management body Groundwater Sustainable Agencies (GSA) Aquifer Local Water Committee (CLE) For irrigation: Water Users’ Association (OUGC)  
Resources considered Collective management of groundwater only Collective management of surface and/or groundwater Collective management of irrigation water

(independent from the origin GW/SW)

Lack of SW/GW integration in the Californian case
Groundwater access rights Overlying right” Free access of overlying land by owners for a reasonable use (not quantified), but SGMA allows the GSA the possibly to limit withdrawal Access right to overlying land by owners. Water use authorizations are allocated collectively by the OUGC and authorized through an administrative procedure from the state In California, access right of land owners is not clearly defined or limited (no cap) but could be under the new SGMA
Subject areas Compulsory on High and Medium priority groundwater basins Necessary on areas designated by the SDAGE since 2009 Compulsory in Water Allocation Area (ZRE) Similar prioritizing approach
Boundaries of the resources considered Defined by the state

then possibility of overlap and multiple local GSAs

Defined by the stakeholders and validated by the state

No overlap of local CLEs over same resources

Defined by state

No overlap, but possibility of multiple OUGC from a same agency

Issues of coordination among different GSAs in CA

Less flexibility for the creation of the OUGC in France, delaying the process

Stakeholders formally represented Agencies 100% local land and water public agencies. No direct private sector involvement Private and public participation more than 50% local authorities, more than 25% users, less than 25% State representatives Public or private organization with internal (farmers)/external (state) legitimacy Direct representation of stakeholders in France and participation of the state. Limited direct involvement of ag. sector in California
Overarching aim Define and implement a Groundwater Sustainability Plan to achieve Groundwater Sustainability and avoid undesirable results defined locally Define and implement the local (ground) water management plan (SAGE) incl. the maxEV and its allocation among water users (Incl. farmers) Ensure that the sum of individual water allocation meets the maxEV defined in the SAGE Similar decentralized planning process with more flexibility in California but a two stage implementation in France
Funding Grant funding (Water bond)  and fee to be defined by the GSA Local funding and support from the river basin agencies Fees defined by the OUGC

Benefit from public subsidies (up to 70%)

Pre-existing groundwater fee in France may facilitate the process
Quantitative targets To be defined in the GSP, by the GSA, validated by the state Define groundwater thresholds for an aquifer and maxEV, validated by the state Thresholds and share of the maxEV previously defined by the SAGE In France, targets are explicitly defined but need to be set locally. In California the GSP have to define and set them

The on-going implementation in both countries will be an interesting learning process for better understanding the challenges of operational collective groundwater management.

Both France and California are shifting towards more local collective management of groundwater as a way to organize and avoid local conflicts over water allocation. The future will show if it works. In France, the direct participation of farmers in the local negotiation process, the existing administrative control of groundwater withdrawals and existing withdrawal fees make the development of local groundwater management institutions easier than in California, where no such equivalent exists. However, existing difficulties in France to over-come cultural inertia, avoid local interferences, and ensure financial and environmental sustainability suggest that in both cases local implementation will likely need assistance from the basin authority and state government and as well as commitment from the local stakeholders to be successful.

Corentin Girard is a post-doctoral researcher at the Universitat Politecnica de Valencia in Spain and visiting scholar at UC Davis Center for Watershed Sciences.

Further Reading

Eaufrance, 2016a, Qu’est-ce qu’un SAGE?

Eaufrance, 2016b, Type de périmètres des SGAE en Janvier 2016.

Figureau, A. G., Montginoul, M. and Rinaudo, J.-D., 2012. Gestion quantitative de l’eau d’irrigation en France : Bilan de l’application de la loi sur l’eau et les milieux aquatiques de 2006. Orléans, BRGM. BRGM/RP-61626-FR: 50.

Guttinger P. Le statut juridique de l’eau souterraine. In: Économie rurale. N°208-209, 1992. L’agriculture et la gestion des ressources renouvelables. Session des 29 et 30 Mai 1991, organisée par Maryvonne Bodiguel (CNRS) avec la collaboration de Michel Griffon (CIRAD) et Pierre Muller (CRA-FNSP) pp. 66-69; doi : 10.3406/ecoru.1992.4454.

Petit, O., 2009,  La politique de gestion des eaux souterraines en France, Économie rurale.

Thoyer, S. et al., 2004, Comparaison des procédures de décentralisation et de négociation de la gestion de l’eau en France et en Californie », Natures Sciences

Sociétés 2004/1, 12, 7-17.

JORF, 2006, Loi n° 2006-1772 du 30 décembre 2006 sur l’eau et les milieux aquatiques Journal Officiel de la République Française, n°303 du 31 décembre 2006, France, Texte n°3/175

http://circulaire.legifrance.gouv.fr/pdf/2010/08/cir_31709.pdf

MEEDDT (Ministère de l’écologie, de l’énergie, du développement durable et de l’aménagement du terittoire), (2008), Circulaire du 30 juin 2008 relative à la résorption des déficits quantitatifs en matière de prélèvement d’eau et gestion collective des prélèvements d’irrigation NOR : DEVO0815432C, Bulletin officiel du Ministère de l’écologie, de l’énergie, du développement durable et de l’aménagement du terittoire, Paris, 2008 (In French)

[1] Administrative declaration if the withdrawal is over 8m3/h or the depth lower than 10m (Guttinger, P. 1992)

[2] Administrative declaration if the withdrawal is over 8m3/h or the depth lower than 10m, authorization if flow is higher than 80m3/h (1992 Water Law)

Posted in Around the World, California Water, Groundwater, Planning and Management, Uncategorized | Tagged | 2 Comments

Better accounting begets better water management

by Jay Lund

groundwater pump

Source: Escriva-Bou et al. 2016

Sustainable use of groundwater in California will require major changes in groundwater management, use, and recharge.  Under the 2014 Sustainable Groundwater Management Act, groundwater basins as a whole are responsible for sustainability.  But millions of people and thousands of governments and private land managers must recharge more water and pump less to achieve this goal, without disrupting existing surface water rights.  How can responsibility and credit for groundwater use and recharge be developed and assessed without debilitating water wars?

State-overseen accounting already civilizes common disputes involving land ownership, money, gasoline, electricity, and weights and measures generally.  Local water utilities measure and estimate water quantities to improve accountability, transparency, and management for their own customers, regulators, system managers, and financiers.  Some groundwater basins, such as Orange County, Santa Clara Valley, and some adjudicated groundwater basins have rudimentary accounting systems to assess fees for groundwater pumping, plan for recharge, or limit pumping.  But California overall lacks a strong unified system of water accounting, particularly for groundwater.

California should join other advanced economies in dry regions and institute a formal water accounting system.  Australia, Spain, Colorado, Texas, and other western states already have stronger and more unified water accounting systems.  A report released last week by the Public Policy Institute of California, in collaboration with university researchers, details 12 lessons for water accounting in California and reviews water accounting in Australia, Spain, and 11 other western states.  The accounting systems vary in their details, but all have a single authoritative accounting of water flows based on measurements and estimates of water availability, use, and flows returning to streams and aquifers after use.

Groundwater Rights

Source: Escriva-Bou et al. 2016

 

For groundwater, stronger water accounting would transparently inform regulators, users, and the public alike on the balance of groundwater use and recharge and the responsibility and credit for pumping, recharge, and net pumping.  Such accounting is needed to assess basin sustainability, assess liability for pumping and credit for recharge, as well as the natural flows of water underground into and between basins.  Without such accounting, agreements, rights, and allocations regarding water are difficult to make and enforce, begetting excessive legal expenses and delays while basin management remains unsustainable.  An accounting framework also makes detection and correction of errors more transparent and efficient.

A stronger state system for water accounting also would benefit the administration of surface water rights, environmental flows, water markets, and more integrated science-based management, which currently suffer from lack of a strong common state accounting system.  The many partial water accounting systems maintained by separate state and local agencies and programs sometimes compound water disputes and weaken each other more than offering common ground to civilize disputes.  A common water accounting system would help civilize and enlighten a host of chronic water conflicts, and provide a scientific basis for resolving many disputes.

How can California get to a stronger and more useful water accounting system?  Australia, motivated by its great 12-year drought, took 10 years to revamp and solidify its water accounting.  California might begin with an independently-led task force involving the major state agencies along with independent experts and stakeholders, commissioned to make recommendations to the Governor’s office and the legislature.

California is already paying most of the cost needed for a credible water accounting system.  Major water utilities already measure or estimate their water sources and uses, usually in automated “supervisory control and data acquisition” (SCADA) systems.  State forethought to organize and automate collection of these data would allow transparent, accountable, timely, and inexpensive incorporation of such existing data for water accounting.  (Smaller users will take more time, but are less important overall.)  The hardest part is organizing  state agencies around a single coherent water accounting framework, which can be supported by locally-collected data and integrated with regional computer models.

Civilizing water conflicts begins with data and an accounting framework.

Jay Lund is a professor of civil and environmental engineering and director of the Center for Watershed Sciences at UC Davis.

Further reading

Alvar Escriva-Bou, Henry McCann, Ellen Hanak, Jay Lund, and Brian Gray (2016), Improving California’s Water Accounting, 28 pp. Public Policy Institute of California, San Francisco, CA.

Alvar Escriva-Bou, Henry McCann, Elisa Blanco, Brian Gray, Ellen Hanak, Jay Lund, Bonnie Magnuson-Skeels, and Andrew Tweet (2016), Improving California’s Water Accounting – Technical Appendix, 177 pp. Public Policy Institute of California, San Francisco, CA.

Improving California’s Water Accounting, report release webcast, Public Policy Institute of California, San Francisco, CA. http://ppic.org/main/event.asp?i=2077

Brian Gray, Ellen Hanak, Richard Frank, Richard Howitt, Jay Lund, Leon Szeptycki, Barton “Buzz” Thompson (2015), Allocating California’s Water: Directions for Reform, Public Policy Institute of California, San Francisco, CA.

Posted in California Water, Groundwater, Planning and Management, Sustainability, Uncategorized | Tagged | 3 Comments

St. Helena, California: Dealing with a Field-of-Dreams Levee, Residual Risk, and a Flood of Controversy

by Nicholas Pinter

A new $37.2[1] million levee in the town of St. Helena, on the floodplain of the Napa River, has a colorful history and has been stirring local acrimony since its inception.  This project illustrates both the attraction of levee protection, in this case protecting a low-income neighborhood (“low income” by Napa standards) hit by disastrous flooding in 1986 and again in 1995, as well as pitfalls of this strategy for long-term risk management.  There are clearly positive elements of the St. Helena levee project, but also numerous missteps that have mired the project in dissent and even, opponents argue, threaten to bankrupt the town.  With important planning and zoning decisions now pending, the St. Helena levee is a case study for other communities to examine before they consider all of the options for flood-risk management.

After the release of a recent journal article on levee protection, one reporter tried to wake me up with the following opening question – “Prof. Pinter, why do you hate levees?”  I laughed in appreciation of a good icebreaker, and then explained how levees, floodwalls, and other structural protections are valuable tools in a diverse toolkit used to manage flood risk.  But levees also come with adverse consequences that need to be rigorously evaluated and balanced against their potential benefits.  Those negative impacts and the need for careful evaluation are often lost in the rush to build new levees or enlarge existing structures, typically in the aftermath of a damaging flood.

St. Helena is a town of about 6,000 people along the Napa River about 20 miles upstream of the City of Napa.  The river there is small, averaging just 46.7 cubic feet per second (cfs) of flow over the duration of record, but subject to flash flooding after intense local rainstorms.  Since 1862, 28 major floods have struck the Napa Valley[2], including 1955, 1963, 1967, 1973, 1978, 1981, 1983, 1986, 1993, 1995, 2002, and 2006.  Most of St. Helena is located a safe distance from the river, but starting in the 1970s, the Vineyard Valley area was developed, including 468 homes, apartments, and mobile homes at risk of flooding[3].  Most of these are in what is now mapped by FEMA as the so-called 100-year floodplain.  During the five-year review process for development of the mobile home park, local residents report that the issue of flood risk was never raised.

Napa Flood

Figure 1 –  The Vineyard Valley neighborhood of St. Helena under water during the 1986 flood.

Intense rain events hit the upper Napa Valley in February of 1986 and again in March of 1995, sending the Napa River over its banks and into the new Vineyard Valley development.  Damages in each event were estimated at over $50 million in St. Helena alone.  During the 1995 flood, over 400 residents of St. Helena were evacuated, and 200 mobile homes in Vineyard Valley were declared a total loss.  In both 1986 and 1995, other communities such as Calistoga and Yountville also were hard-hit, including inundation of much of downtown Napa.  As described by the Napa Valley Register, “Overnight, the Napa River swelled from a modest tributary of San Francisco Bay to a wrathful Amazon.”  The 1986 flood killed three people, forced the evacuation of over 2,500, and caused total damages estimated at $100 million2.

A typical pattern in flood response is that it takes a one-two punch to motivate any large-scale action to address flood risk.  The 1995 flood in Napa was that second punch.  Surveying the damage, Napa County officials dusted off a flood-control plan initially drafted by the Corps of Engineers but defeated by a voter referendum in the 1970s.  The original Corps flood control plan was considerably reworked and, particularly in the City of Napa, many forward-thinking elements were added, including channel habitat preservation and reconnection of the historic floodplain.  Flood control was now put to the voters again, in the form of Measure A, a half-percent county sales tax, which was passed in March of 1998 with a two-thirds voter majority.  With local cost-share funding secured through the referendum, Napa County began moving forward with the large-scale flood plan in Napa, with smaller portions of the funding apportioned to other communities along the river.

St Helena plans

Figure 2 –  The positive side of flood control. As part of the St. Helena project, a total of 17 mobile homes were permanently and the flood wall set back from the river.

In St. Helena, plans were drawn up that focused on a large levee and floodwall to protect the Vineyard Valley area, as well as several other elements.  These other elements of the project included bank stabilization, removal of a channel constriction, internal stormwater management, and excavation of a storage area outside the levee (a “terrace,” the project calls it) planted in native vegetation.  The channel restriction, for example, involved the removal of 17 mobile homes and the associated land closest to the river, which opened that area to better pass flood flows.  This bend in the river channel represented a chokepoint during floods, significantly obstructing flow and raising water levels in that area and upstream.  Removal of these homesites and augmenting the conveyance capacity of the channel at this chokepoint certainly lowered flood danger by both reducing at-risk infrastructure and by lowering water levels during future floods.

Although the St. Helena project included several forward-thinking elements, it remained much more of an “old school” structural flood-control plan than what was implemented in Napa.  The St. Helena plan centered on approximately 2,000 ft of floodwall surrounding the Vineyard Valley mobile home park and another ~2,000 ft of levee that extends from the floodwall to the north and west.  As now required of urban levees in California, the system protects to the “200-year” level – that is, designers of the levee and floodwall have affirmed that they will keep out floods up to those with a 0.5% chance of occurring in any year.

On a map the St. Helena levee is relatively small, a tiny fraction of the length of the systems that protect the Central Valley or great alluvial floodplains of the Midwest.  But its height is impressive.  Standing on the new levee crest above the Napa River, one can almost imagine looking out on the Sacramento or Mississippi River.  The levee is also proportionally wide, with a crest 15-20+ feet across, wide enough to meet requirements for much larger rivers and floodplains.  Wide enough, in fact, to carry two full lanes of traffic.  Indeed, the initial St. Helena planning documents[4] called for a multi-function levee that would also serve as a new roadway.  This new road would have crossed the floodplain and the river across a new bridge, connecting St. Helena to the Silverado “wine trail” on the northeast bank.  Currently that connection is across the Pope Street bridge, a historic stone structure built in 1894 and so narrow that it is terrifying to cross even when the driver coming the other way hasn’t spent the afternoon sampling the latest vintages.  Using flood-control funding to simultaneously serve another goal might not be illegal, but it raises questions about priorities in design details.  In this case, the proposed bridge link was rejected after litigation focused on its environmental impacts, but before levee construction.  Nevertheless, the width of the St. Helena levee retained the width of a road to nowhere, as well as – importantly – a path that took the levee far wide of the housing it was funded to protect, enclosing a broad swath of floodplain undeveloped and empty except for rows of grapevines.  More on this in a moment.

Another interesting aspect of the St. Helena levee is the funding to plan and design the project.  The city obtained an $8 million grant from FEMA’s Hazard Mitigation Grant Program (HMGP).  HMGP uses a slice of FEMA’s total disaster-related funds to promote “mitigation,” meaning actions taken by communities to lower their overall exposure to future disasters.  Flood-mitigation strategies favored by FEMA nationwide include buyouts and relocation of repeatedly flooded homes or elevation of floodplain structures up beyond the reach of future floods.

FEMA carefully monitors HMGP projects to make sure that taxpayer funds are used for their intended purpose.  In 2013, when FEMA audited St. Helena, the city was unable to account for a large block of HMGP money.  Among project expenditures, the city had spent $1.64 million on lobbying expenses, reportedly including lavish entertainment expenses in Washington aimed at securing Army Corps of Engineers and other federal funding for levee construction.  When FEMA reviewed the city’s books, it disallowed $1.9 million in expenses, requiring St. Helena to withdraw this amount from its operational accounts.  Further local acrimony ensued because the city repaid the FEMA money without adequately, some argue, disclosing the financial missteps and the resulting impacts on city finances.  This repayment resulted in a $1.5 million budget deficit and significant cuts to city services.

The details above are a selection of the complaints voiced by local levee opponents in St. Helena.  This dissent contrasts with the broad consensus surrounding the much larger flood-control measures implemented in the City of Napa.  Large public projects never reach perfect consensus, but the Napa Project solicited input from a broad range of stakeholders and integrated these opinions in final project designs.  In contrast, the St. Helena project continues to roil that community even now that the levee is complete and a done-deal.

The final shoe – probably the most problematic element of the St. Helena flood-control debate – is now dropping, five years after the levee’s completion.  The current issue results from the unusual pathway of the levee, which sweeps well north and west of the neighborhoods previously flooded and includes 16.9 acres of undeveloped vineyard land.  Undeveloped until now, that is.  Just 17 days before the passage of Measure A, the mechanism that funded large-scale flood engineering throughout Napa County, much of the empty floodplain land behind the St. Helena levee was purchased by a private developer.  On Sept. 8, 2010 the developer submitted plans to convert the empty agricultural land behind the levee into high-density residential development, including 87 new residential units[5]. This despite an explicit provision in Measure A that “none of these projects are intended or designed to encourage population growth.”

Levee Sniff Test

Figure 3 –  The Levee Sniff Test

My research group has worked hand-in-hand with floodplain residents to provide them planning guidance and technical expertise.  We’ve also studied levee projects that would increase flood heights for neighbors, increase long-term flood risk, or degrade habitats, sometimes in exchange for very limited local flood-protection benefits.  After struggling with this balancing act time and again, we’ve proposed a three-step “levee sniff test” to preliminarily judge any proposal.  New or enlarged levees and floodwalls may be an appropriate solution if the system is designed to protect floodplain infrastructure that is:

  1. concentrated,
  2. high in value, and
  3. pre-existing.

The most crucial – and often the most politically fraught – of these criteria is the third.  The worst case is construction of “field of dreams” levees – new, expensive, often muscular levees surrounding undeveloped or sparsely occupied floodplain land.  “Build it and they will come” – field-of-dreams levees are meant to attract new construction and development on the floodplain.  Political leaders see expansion of their local tax base, and developers salivate over the prospect of transforming low-cost floodplain land into urban real estate as soon as the new levee “solves the problem of flooding forever.”

By intent or by accident, the St. Helena project created a “field of dreams” levee.  The original position of the levee was set by the desire of the city to piggyback a long-sought transportation project onto available flood-control funding.  A private developer saw an opportunity for windfall profits and snapped up this floodplain acreage.  What remains unclear is why, when plans for the roadway were scrapped, did St. Helena not downsize its levee?  Local levee opponents see nefarious motives here, and the optics are not good.  In 2008-2009, local residents had proposed several possible levee alignments that hugged the edges of existing neighborhoods that needed protection.  These alternatives would have eliminated the “field of dreams” issues, cut construction costs, and would have significantly reduced future flood levels for neighboring properties outside the levee.  But these alternatives were rejected at the April 14, 2009 meeting of the City Council.  Why? Perhaps simply a result of frustration at the grassroots opposition and the desire to move forward with the existing blueprint, however much conditions had changed since those plans were drawn up.

“Residual Risk – the small but real possibility that a levee may fail or be overtopped during future floods.”

So past mistakes aside, why not fill in every square inch of land behind a levee once you’ve got one?  The problem with levees, and with field-of-dreams levees above all, is that no type of structural flood protection can ever reduce the flood risk to zero.  Even the strongest levee or floodwall carries a “residual risk” of failure or overtopping during large floods.  Furthermore, having flood waters pour over or burst through a tall barrier turns the gradual process of floodplain inundation into a much more violent, dangerous, and damaging event.  The history of occupation of U.S. floodplains is a history of levee failures, with headlines almost every year bringing footage of disastrous levee failures somewhere in the country.  One levee system on the Mississippi River, not an atypical one, was breached 14 times through its history, only to be patched and raised each time, in the process driving up flood levels for the next event and contributing to the next failure.  Expert after expert, blue ribbon panel after panel, has implored engineers, local leaders, and floodplain residents to not forget about residual risk.  Brig. Gen. (Ret.) Gerald Galloway, former commander of the US Army Corps of Engineers puts it this way, “Let no one believe that because you are behind a levee, you are safe” (Galloway, 2005).  The point has also been made more bluntly, “There are two kinds of levees … [t]hose that have failed and those that will fail” (Martindale and Osman, 2010).

“Developers and home builders may be gone, but residents of Natomas will be there and are the ones who are rolling the residual-risk dice year after year.”

Neglecting residual risk of flooding behind levees creates a false sense of security for residents and a lunatic calculus in which the local community can find itself with far greater long-term flood risk than before the levee was built.

California has made these mistakes before.  In fact, the leading example of a “field of dreams” levee, discussed in floodplain management circles around the world, is Natomas on the northwest side of Sacramento.  The Natomas Basin is ringed by 42 miles of levees, encompassing approximately 53,000 acres of the floodplains of the Sacramento and American Rivers.  This land was sparsely populated until roughly 1990.  Despite a tangled history, the Natomas system was built and they did come.  On-going levee construction, particularly improvements initiated in 1992, ushered in a wave of development.  As of 2010, Natomas was home to over 22,800 structures, the large majority of them residential units and home to more than 90,000 people[6].  The City of Sacramento currently plans to permit up to 1,000 additional single-family homes per year, 500 multifamily residential units per year, and unlimited industrial, commercial, and retail construction behind this levee[7].  Today, total property in Natomas at risk of flood damage, should the levee fail or be overtopped, exceeds $8.5 billion, with flood depths that could reach 25 feet[8].  Heroic efforts are now underway by the Sacramento Area Flood Control Agency, the California Central Valley Flood Protection Board, and the Corps of Engineers to patch deficiencies in the Natomas levee and raise the overall protection provided by the system.  When that huge – and hugely expensive – effort is complete, the State of California, the Corps, and FEMA will sign off that they have reduced the statistical chance of catastrophic flooding in Natomas to 0.5% per year (less than once every 200 years, on average).  That is a high level of protection by US standards, and engineers and leaders who are implementing the project will be justifiably proud of their accomplishment.

But … our country’s 400+ year history with levees also tells us that such claims of almost complete flood protection have often been repeated, and almost always were over-stated.  Lots of reasons why this has happened in the past, and many of those reasons hold true for the future.  But even at face value, a 0.5% exceedance probability for a system now protecting $8.5 billion in property translates – crudely – into up to $42.5 million in risk each year.  If those 22,000+ homes and other structures had already been there before the levee (concentrated, high-value, and preexisting), then this annual $42.5 million in residual risk would have been a necessary tradeoff.  But because Natomas was a field-of-dreams levee built intentionally to create new floodplain infrastructure, the large majority of this $42.5 million/year is all-new and added risk.

Who bears this residual risk if (some would say “when”) California’s drought turns to flood and hands us a “>200-year flood?”  Or a lesser flood that finds a chink somewhere in the 42-mile long, gopher-prone armor that surrounds Natomas?  Developers and home builders may be gone, but residents of Natomas will be there and are the ones who are rolling the residual-risk dice year after year.  So too are all US taxpayers, since we bankroll disaster relief.  Federal expenditures for disaster relief have averaged ~$35 billion per year in recent years[9], equivalent to about $400 per year per US household.

Residual risk also can be borne by the governmental agencies that facilitate “field of dreams” levees.  Legal liability came to roost in California in 2003, when the Court of Appeals found the state liable for $500 million in damages resulting from a levee break on the Yuba River in February of 1986, the same storms that flooded St. Helena.  The case was Paterno v. State of California, and although the state neither built nor maintained the levee that gave way, the court found that it was responsible for inadequate maintenance and management of the system.  And liability extends to counties and towns as well; for example, California Assembly Bill 80 made local jurisdictions liable for “property damage caused by a flood [if they] … unreasonably approv[e] new development in a previously undeveloped area[10].”  In the Paterno case, the financial hit of that $500 million decision shook the financial structure of the entire state, such that California was forced to borrow funds from Merrill Lynch in order to pay the claims against it[11].

So where does St. Helena and its levee fit into this broader picture?  This levee and the new construction proposed behind it are tiny compared to what has gone onto Sacramento area floodplains, St. Louis floodplains, Houston floodplains, and others.  But the principles are the same, and the potential consequences for a small community like St. Helena are proportionally even more threatening than for a large city.  The St. Helena Vineyard Valley levee was built to protect residents who had the misfortune of living in a neighborhood built on the edge of the Napa River and far into the floodplain, a neighborhood that should not have built in the first place.  That was certainly mistake number one.  But after repeated and devastating floods, those residents were justified in seeking a mitigation solution.  The second crucial misstep occurred in 2009, when the city approved a levee map that enclosed a large area of floodplain empty except for rows of grapevines.  Whether by nefarious purpose or just fatigue, St. Helena opened the door to the crucial and difficult decision now in front of them – whether to bow to the pressure and temptation of approving development of that empty land behind their levee.

vineyard valley levee

Figure 4 – View from Vineyard Valley Levee access road, towards the east, showing current conditions of the proposed development area. Figure IV.A-3a in Hunter Valley Subdivision Project, Draft EIR, Dates 5/29/2012.

One concern certainly on the minds of St. Helena city leaders is the threat of litigation if they deny the development plans in front of them.  When such cases go to court, plaintiff lawyers typically cite the Fifth Amendment of the US Constitution, which states that “private property [shall not] be taken for public use, without just compensation.”  The legal claim is that refusal to allow development of the owner’s land constitutes a “takings” of the value of that land.  The St. Helena situation is typical of many examples where the legal threat of a takings claim is used to thwart zoning or planning to manage flood risk and other natural hazards.  Developers and their lawyers argue that zoning to prevent development is unjustified, arbitrary, and an infringement of the rights of landowners.  On the contrary.  The St. Helena developer purchased agricultural land in a floodplain at a price consistent with those conditions.  Despite the construction of a levee at taxpayer expense surrounding that land, it remains a floodplain.  The limitation on building expensive homes and apartments on that floodplain is imposed by nature, not the City of St. Helena.

Fear of lawsuits and potential liability is a tangible pressure on a town like St. Helena.  But in considering development of floodplain land behind a field-of-dreams levee, these communities are perhaps looking at the lesser threat.  Bowing to the will of the developer dodges a likely “takings” lawsuit, but loads St. Helena with new residual risk – risk that is small as an annual percentage, but large in total magnitude.  The mean value of a detached home is St. Helena is $640,000 and an attached unit is $401,000[12].  Given current plans for 51 new single-family homes, 11 granny units, 24 multi-family units5, and a typical value of 50% content damages for flood-loss estimates, these 87 new units could suffer $49 million in damages if that area were inundated.  After the 1995 flood, residents of Vineyard Valley sued the City, and residents of the proposed new development could take the same action.  The 2003 Paterno decision against California amounted to just 0.5% of the state’s total budget that year.  For comparison, the City of St. Helena, with revenue to its general fund of $10.5 million in FY 2015/16, could face a financial hit totaling 469% of its annual resources.  In other words, the legal liability from the proposed new development could bankrupt the city nearly five times over.

“The legal liability from the proposed new development could bankrupt the city nearly five times over”

St. Helena was founded in the mid-1800s, near enough the Napa River to gain the benefits of that proximity, but up and off the floodplain.  However beginning in the 1970s, the town suffered the same magnetic pull as countless other communities across the US – succumbing to pressures for growth and the attraction of empty land ever closer to the river.  Located deep in the Napa River floodplain, the Vineyard Valley neighborhood was reviewed and approved, reportedly without even discussing the possibility of flooding.  This was an oversight for which residents paid dearly in 1986 and again in 1995.  Mistake followed mistake: land that never should have been developed, an expensive levee that has already sent the town into financial distress and political discord, and a levee map that somehow enclosed much more floodplain land than the neighborhood it was designed to protect.  St. Helena now has a last chance to bring this cascade to an end and avoid construction of 87 new homes behind their field-of-dreams levee.  Floodplain managers, river scientists, and prudent leaders worldwide counsel that levee protection is never absolute, and that even the tallest and strongest wall comes with an inherent residual risk, a small but real possibility that it may fail or be overwhelmed during future floods.  For concentrated and existing floodplain infrastructure, levees can be the right solution, and residual risk preferable to no action at all.  But towns like St. Helena should understand that levee protection brings a range of consequences, including the possibility of multiplying, not diminishing, the long-term risk of damage and potentially even loss of life in their community.

Nicholas Pinter is a professor in the Department of Earth and Planetary Sciences and an affiliate of the Center for Watershed Sciences. This article was developed with assistance from Megan Nguyen, a junior researcher at the Center for Watershed Sciences. 

Further Reading

[1] Report to the St. Helena City Council, Council Meeting of January 26, 2016

[2] City of Napa. 2009.  Hazard Mitigation Plan, 2009 update.

[3] City of St. Helena, 2007.  Project Summary: City of St. Helena Flood Protection and Flood Corridor Restoration Project

[4] e.g., “Enhanced Minimum Plan” dated 7/2003; City of St. Helena Staff Report dated 4/14/2009

[5] Hunter Subdivision Project, Draft EIR, dated 5/29/2012 (Sch: 2012 032048), Available from http://cityofsthelena.org/sites/ default/files/Hunter%20Public%20Review%20Draft%20EIR_%20052912.pdf

[6] 2010 Census data; North Natomas + South Natomas.

[7] City of Sacramento, 2015.  Fact Sheet: Next steps for Natomas with a revised flood map, dated 3/24/15.

[8] US Army Corps of Engineers, A. Kirchner, 2010, Road to a Chief’s Report: American River Watershed [Common Features] Project, Natomas Basin, Sacramento and Sutter Counties, California.

[9] Disastrous Spending: Federal Disaster-Relief Expenditures Rise amid More Extreme Weather. Center for American Progress, 2016.

[10] California Senate Judiciary Committee, 2007.  AB 70: Bill Analysis.  Available from http://www.leginfo.ca.gov/pub/07-08/bill/asm/ab_0051-0100/ab_70_cfa_20070711_145337 _sen_comm.html

[11] Vogel, N., 2005.  A wave of relief after 1986 flood.  Los Angeles Times, Aug. 15, 2005.  (Available from articles.latimes.com/2005/aug/15/local/me-flood15)

[12] 2013 data from http://www.city-data.com.

Pinter, Nicholas et al. 2016 Modeling residual flood risk behind levees, Upper Mississipi River, USA. Environmental Science & Policy. 58 131-140

Posted in Floodplains, Planning and Management, Uncategorized | Tagged , , | 4 Comments

Instream flows: Five features of effective summer flow strategies

By Ann Willis

As summer begins and stream flows drop throughout California, concerns resurface about whether there’s enough water to support critical ecosystems. Environmental flows have long been a contentious issue, often presented in conflict with existing water use. But there are five key ideas worth remembering as water users and regulators throughout the state consider how best to support environmental objectives during these periods of naturally low stream flows within the framework of existing water laws and desired water use.

  1. Location matters.

Reduced cold water habitat during the summer is a common concern in a state that supports a number of cold water species, including spring-run Chinook and coho salmon. But while warm water or dewatered streams may appear alarming, they can be part of a stream’s natural condition. Smaller, headwater streams are more likely to have cooler water (assuming there’s snowmelt, rainfall runoff, or groundwater-fed springs to wet the channel).

But larger streams, areas that are far downstream from headwater sources or groundwater contributions, or streambeds of porous gravels are naturally warmer or even dewatered during the summer. These seemingly undesirable, intermittent flow conditions play an important role in supporting biodiversity. Providing instream flows to support cold-water species in these areas won’t overcome natural limitations to desirable habitat, and may promote undesirable, non-native species over native ones.

  1. Objective matters.

Instream flows are often proposed as a way to address a regulatory objective, like recovery of a target species. But each species has different needs at different life stages, so clearly identifying the objective for instream flows is important. Is it to reduce or maintain desirable water temperatures? Ensure passage upstream? Improve or sustain physical habitat? Different objectives have different flow and water quality requirements. Knowing what you’re planning for helps identify when, where, how much, and what quality of water is useful – or not.

  1. More water is not (necessarily) better.

When stream flows are reduced by diversions or regional groundwater use, and degraded ecological conditions also exist, it’s logical to conclude that adding water to the stream will resolve those ecological impairments. Except sometimes it doesn’t.

In general, if stream water is already warm, or the contributing sources are warm, adding water will not cool the stream down. But there are other situations where increasing stream flow can help. Studies show that adding water tends to have the greatest benefit when it’s used to address extreme low flow or water quality conditions – in the right location (see #1).

In the Shasta River, habitat conditions for fall-run Chinook improve the most when water is added to the lowest observed seasonal flows, when fish return to the system, but show little to no effect as these flows increase.

instreamflows

Additional streamflow improved available pool habitat in the Shasta River the most when water was added to the lowest baseflows. From Willis et al. (2015)

In an on-going study of oversummering habitat for coho salmon, preliminary results similarly show that additional water tends to have the greatest benefit when water temperature conditions are at their warmest and stream shade has yet to fully develop. But aside from those extreme conditions, adding water provides marginal, if any benefit. These unexpected findings have important implications, most notably that:

  1. Land and water use do not equal ecological degradation.

Over 80% of the Earth’s land is influenced by humans. Agriculture accounts for almost 70% of human water use. Given the extent of our footprint, achieving conservation goals by reserving habitat from human use or eliminating water use is insufficient and infeasible. Large-scale conservation efforts must consider how to create sustainable

A rice farm in the Yolo Bypass near Sacramento. Photo by Carson Jeffres

A rice farm in the Yolo Bypass near Sacramento. Photo by Carson Jeffres

biodiversity within human-dominated landscapes. This is reconciliation ecology.

Studies show that successful reconciliation is possible. In California’s Central Valley, rice farmers cooperate with water managers, scientists, and regulators to provide floodplain habitat on rice fields for juvenile Chinook salmon, creating some of the most successful growing conditions outside of hatcheries.

Photos by Carson Jeffres, UC Davis

Big Springs Creek in 2008, the year before fencing (left), and six months after cattle exclusion. Photos by Carson Jeffres, UC Davis

In the Shasta Valley, The Nature Conservancy demonstrated how to operate a cattle ranch – including diversions for irrigation –  while restoring and sustaining Big Springs Creek, the largest and most robust cold-water stream

Orchards of walnuts (above) and almonds (below) may be viable sites for groundwater recharge, though the potential for water damage to such high-value crops adds risk.

Orchards of walnuts (above) and almonds (below) may be viable sites for groundwater recharge, though the potential for water damage to such high-value crops adds risk. Photo by David Doll

for juvenile coho salmon in the lower Klamath Basin. Researchers are exploring how flooding fields can promote groundwater recharge while maintaining agricultural activities. These projects show the importance of reconciling land and water use with environmental objectives, as well as their potential for success.

So how do you design a management strategy for a stream system that reconciles ecological and water use objectives?

  1. Focus on QQST – Quantity, Quality, Space, and Time – to achieve long-term, viable, multi-objective water use.

Water management frameworks should explicitly recognize that realistic potential exists to support multiple and competing water uses (i.e., “co-equal goals”) when a stream exists in a reconciled state. QQST is a guiding principle to this framework that provides a method to efficiently identify competing water demands and develop flexible solutions.

Conceptual figure

A conceptual diagram of a stream system as it transitions from a baseline state, through a degraded condition, and into recovery with the implementation of interim, transitional, and long-term measures. From Willis et al. (2013)

Using the QQST principle, three types of management strategies can be developed to achieve established co-equal goals: interim (or “emergency”), transitional, and long-term measures.

Each management strategy is implemented depending on the condition of the aquatic ecosystem, which can be defined in various stages of degradation, recovery, or reconciliation.

Recent actions by the State to curtail water restrictions during the California’s severest drought conditions, and then ease water restrictions while implementing long-term policies to sustain California’s water resources (e.g., the Sustainable Groundwater Management Act) are good examples of the various types of interim, transitional, and long-term measures that can be used.

As the concepts of co-equal goals and reconciled ecosystems become more widely applied, approaches like QQST can help guide water users, resource managers, and agencies to effective and sustainable water management strategies.

Ann Willis is a staff researcher with the Center for Watershed Sciences. Her work focuses on management strategies to balance water resources to achieve co-equal goals of human and environmental water use.

Further reading

Willis et al. 2013. Water resources management planning: conceptual framework and case study of the Shasta Basin.

Willis et al. 2015. Instream flows: New tools to quantify water quality conditions for returning adult Chinook salmon. Journal of Water Resources Planning and Management.

UC Davis Center for Watershed Sciences. Nigiri Project: Growing Rice and Salmon on a floodway.

Bachand et al. 2015. Capturing El Nino for the underground. California Waterblog.

Yarnell et al. 2015. Functional flows in modified riverscapes: hydrographs, habitats and opportunities. Bioscience.

Allan JD and Castillo MM. 2007. Stream Ecology.

Rosenzweig ML. 2003. Reconciliation ecology and the future of species diversity

Sanderson et al. 2002. The human footprint and the last of the wild

Cosgrove and Rijsberman. 2014. World water vision: making water everybody’s business

Posted in California Water, Conservation, Planning and Management, reconciliation, Sustainability | Tagged | 2 Comments

How bad is water management in California?

by Jay Lund

California’s combination of climate, native ecosystems, and human uses makes water management inherently hard, unsatisfactory, and evolving.  California is doomed to have difficult and controversial water problems. No matter how successful we are.

California is one of the few parts of the world with a Mediterranean climate (Figure 1).  These climates tend to be dry (not much water), attractive places to live and farm (bringing high water demands), with mismatch between wetter winters and dry summer growing seasons.  The scarce water supply in the wrong season for human activities makes human management of water problematic for native ecosystems.

Mediterranean climates are special places, socially, economically, and environmentally with unavoidably challenging water problems.

California’s ongoing drought has provided opportunities to scrutinize its water management.  Droughts are trials that help identify problems and solutions.  The current drought has prompted several water management innovations in California, including state efforts to require local groundwater management, tightening water rights administration, and increases in water prices and urban water conservation.  Every drought is different, affecting a somewhat changed water system which serves a changing society, economy, and ecosystem.  Droughts historically catalyze strategic changes in California’s water management system.

If California is doomed to have hard water problems and unsatisfactory water solutions, how is California doing relative to other parts of the world blessed and burdened with Mediterranean climates.  Table 1 roughly compares the world’s regions with Mediterranean climates in terms of the population they support, economic wealth per capita, size of their agricultural economy, and (very roughly) condition of their native freshwater aquatic ecosystems.

As a person, native fish, or farmer, in which Mediterranean climate would you rather live?

Table 1. Comparison of Water Management Success for the World’s Mediterranean Climates (Population and economic data from Wikipedia.com.  Agricultural economy data from FAO Statistical Pocketbook 2015. Ecosystem assessment is purely subjective.)

Country/ State Population (millions) Wealth (GDP PPP/person) Food Production ($ billion) Native Freshwater Aquatic Ecosystem Condition
California 39 $62,000 $45 Struggling, much diminished
Algeria 39 $13,000 $8 Largely eliminated
Australia 24 $68,000 $25 Substantially eliminated
Chile 18 $22,500 $8 Substantially eliminated
Greece 11 $26,000 $6 Largely eliminated
Israel 8 $36,000 $3 Largely eliminated
Italy 61 $35,600 $29 Largely eliminated
Morocco 33 $7,000 $9 Largely eliminated
S. Africa 54 $12,500 $13 Struggling, much diminished
Spain 46 $43,000 $32 Largely eliminated

California is perhaps the world’s best-performing region with a Mediterranean climate in terms of managing water for both humans and ecosystems.  California can learn from other regions, but is certainly not a laggard in terms of environmental and economic performance among Mediterranean climates.  We do not do as well with water as we would like, and we must find ways to do better, but California nevertheless does relatively well in managing water.

This is not to encourage complacence, but to discourage panic.  There seems little reason to support an overall revolution in most of California water management, despite ongoing needs to make substantial improvements.  California always will need to pay attention to making improvements in how water is managed, to reduce the inherent dissatisfactions of a populous, prosperous, and agriculturally productive region with a dry Mediterranean climate.  Organized and persistent attention with high but realistic expectations has been key to California’s historical success and to continued change and progress.

Further readings

Alexander, B.S., G.H. Mendell, and G. Davidson (1874), Report of the Board of Commissioners on the Irrigation of the San Joaquin, Tulare, and Sacramento Valleys of the State of California, Washington: G.P.O., 1874.

Bonada, N. and V.H. Resh (2013) “Mediterranean-climate streams and rivers: geographically separated but ecologically comparable freshwater systems,” Hydrobiologia, Volume 719, Issue 1, pp 1-29. http://diposit.ub.edu/dspace/bitstream/2445/48188/1/629547.pdf

Gasith, A. and V. H. Resh (1999), “Streams in Mediterranean Climate Regions: Abiotic Influences and Biotic Responses to Predictable Seasonal Events,” Annual Review of Ecology and Systematics, Vol. 30: 51-81 (Volume publication date November 1999), DOI: 10.1146/annurev.ecolsys.30.1.51

Hanak, E., J. Mount, C. Chappelle, J. Lund, J. Medellín-Azuara, P. Moyle, N. Seavy (2015), What If California’s Drought Continues?, Public Policy Institute of California, San Francisco, CA, August 19, 2015

Lund, J. California droughts precipitate innovation 21 January 2014, CaliforniaWaterBlog.com

Mount, J., B. Gray, C. Chappelle, J. Doolan, T. Grantham, and N. Seavy (2016) Managing Water for the Environment During Drought: Lessons from Victoria, Australia, PPIC, San Francisco, CA, June.

Pisani, D. 1984. From the Family Farm to Agribusiness: The Irrigation Crusade in California, 1850–1931. Berkeley: University of California Press.

Underwood, E.C. , J. H. Viers,  K.R., Klausmeyer, R. L. Cox, and M. R. Shaw (2009), “Threats and biodiversity in the mediterranean biome,” Diversity and Distributions, (Diversity Distrib.) (2009) 15, 188–197

Posted in Drought, Planning and Management | Tagged | 12 Comments

California Water Made Simple

California_water_explained_2dCelebrating end of the academic year, and the need to grade papers, here is a reprise post from January 29, 2014.

There’s only so many acre-feet of water jargon the public can absorb during a drought. Here’s a primer that avoids wading into cubic-feet-per-second, appropriative water rights, overdraft, conjunctive water use and the like.

Further reading

http://CaliforniaWaterBlog.com

Hanak, et al. 2011, Managing California’s Water: From Conflict to Reconciliation, Public Policy Institute of California

http://mavensnotebook.com

Posted in Uncategorized | 3 Comments