Monday, August 24, 2020

Casitas Draft Comprehensive Water Resources Plan


Casitas Municipal Water District is developing a Comprehensive Water Resources Plan (CWRP) to provide information to guide future management of our water supply. The draft document currently recommends almost $160 million in capital projects, most of which is dedicated to the pursuit of imported water from the State Water Project. The fiscal impact to the ratepayer is left for future work. However, although it is not highlighted in the document, the CWRP clearly demonstrates the community’s ongoing response to changing conditions, and the very real capacity for sustaining our local water supply without the cost of imported water.

Updated Models:

The Draft CWRP document contains valuable information on water demand and supply for the largest water district in the Ojai Valley. The updated Lake Casitas Yield Model estimates that the safe yield from Lake Casitas has been reduced by 15% since the 2004 model. This is primarily a result of lake sedimentation, changes to the Robles Diversion, and the impacts of a changing climate. SAFE YIELD is defined as the largest amount of water that can be drawn from Lake Casitas every year in the period of record, without storage dropping below the minimum allowable storage level.

However, the good news is that the actual demand for water has declined to match the changing conditions. Reduced demand is to some degree a result of the policies developed in the Water Efficiency and Allocation Program (WEAP, 2019), which reduce customer allocations according to the lake storage. Incorporating this demand reduction into the Lake Casitas Yield Model results in the more realistic concept of “Safe Demand.”

Safe Demand is the largest amount of water that can be drawn from Lake Casitas every year in the period of record when demand is reduced based on Lake level according to the WEAP policy. - CWMP

The updated Lake Casitas Yield Model now accounts for the demonstrated reductions in water consumption during drought periods. When accounting for climate change, the projected “Safe Demand” of 10,700 AFY on Lake Casitas is approximately half of the assumed Safe Yield, yet this is well within the range of current water use. In fact, according to the CMWD website, current lake demand is 7,381 AFY, reflecting more than 30% conservation of Safe Demand as recommended by the WEAP during stage 3 drought. Therefore, according to the updated modeling presented in the draft CWMP, the community is well on the path to sustainable use of Lake Casitas.

Risk Assessment:

Rather than build upon this favorable conservation trend, the CWRP inflates the projected demand on Lake Casitas in a risk assessment designed to demonstrate the need for significant investment in “new” water supplies.

The report acknowledges that;

Casitas water demand in the past five years has been considerably lower than 17,500 AFY, reflecting the willingness of Casitas customers to modify water use practices in response to the drought.

But for the purpose of analyzing future scenarios;

Casitas staff felt it was reasonable to assume a permanent savings of 10% from the 2016 UWMP forecast. Thus, the effective Casitas UWMP demand estimate used in the CWRP analysis was 15,750 AFY.

It is important to note that current water use is estimated at 7,381 AFY (CMWD website, Aug 2020.) This is more than 3,000 AFY (30%) below the Safe Demand of 10,700 AFY, or a full 60% reduction from the 2016 UWMP projected demand.

The CWRP presents a Risk Analysis based upon a seemingly arbitrary demand of 13,000 AFY, with the assumption that no emergency measures would be taken. This is approximately 2,500 AF greater than Safe Demand. Not surprisingly, this analysis resulted in a long-term supply deficit, for which;

Modeling showed a supplemental supply of 2,500 AFY would adequately mitigate that risk if achieved within one to five years.

The report goes on to recommend a suite of projects totaling over $150M to secure the “missing” 2,500 AFY. The majority of this money is required for large infrastructure proposals to connect to the State Water Project. (Note that 2,500 AFY is less than half of annual evaporation losses from Lake Casitas.)

The table below provides a summary of the various Supply and Demand estimates:

Community Resilience:

Throughout the Ventura River watershed, the community has exceeded recommended reductions in water allocations. This includes customers of the other water districts who all share in the limited local supply. This dramatic reduction in water use is largely in response to the recent catastrophes, including the Thomas Fire and severe drought. The community has clearly demonstrated the ability for adaptation in a time of need. And as the CWRP recognizes, some of these changes have resulted in a permanent demand reduction through lawn replacement and other water saving measures.

CMWD recognizes the importance of working with the community it serves:

“The main mechanism to respond to water supply conditions is to rely on informed customers working in partnership with Casitas to limit water use to no more than the assigned water allocation and support the water use limitations with appropriate conservation penalties for water use in excess of the assigned, or adjusted, allocation.” - WEAP 2019

Yet at the same time, CMDW appears hesitant to fully develop this community partnership:

Customers have a limit to their tolerance for being asked to conserve. Casitas will need to gauge public perception on this topic when the WEAP is updated.” - CRWP 2020

In the meantime, the community has successfully accomplished the sustainable “Safe Demand” as determined by the updated Lake Casitas Yield Model by incorporating WEAP demand reductions in response to lake levels.

Demand Management:

Demand management is always more cost effective than infrastructure dependent new supply projects. And the Ventura River community is just getting started. Numerous local projects were identified in the Ventura River Watershed Plan, and several initiatives are currently underway to plan and implement decentralized solutions aimed at improving conditions in the watershed. Indeed, the watershed plan (which CMWD participated in) developed the consensus objective of maintaining independence from imported water based upon the numerous emerging initiatives identified in the report.

Sufficient local water supplies to allow continued independence from imported water and reliably support ecosystem and human (including urban and agricultural) needs in the watershed now and in the future, through wise water management. “ – Ventura River Watershed Management Plan 2015

However, the CWRP relegates Demand Management to the status of “conditional strategy,” only pursuing such local options if plans for the State Water Project connection do not come to fruition.

Additional Demand Management: Because the CWRP planning policies already include a 10% demand reduction compared to the most recent UWMP, the long-term supply gap was addressed through developing new water supply projects and additional demand management was recommended as a conditional strategy. It is recommended that Casitas develop a Water Conservation Plan to evaluate the potential savings and cost effectiveness of various conservation measures.

Cost Benefit Analysis:

As recommended in the CRWP, the potential savings and cost effectiveness of various conservation measures needs to be carefully examined and compared with the more expensive infrastructure projects. The community deserves a fair and unbiased accounting because it is they who will bear the cost of these decisions.

In 2011, a group from the Bren School of Environmental Science and Management at UCSB developed a watershed model and investigated the cost effectiveness of a suite of infrastructure and consumer- based projects. Aside from the effectiveness of “consumer-based” programs such as re-landscaping and greywater, their report, Sustainable Water Use in the Ventura River Watershed, determined that:

Raising water rates to reflect the true value of water within the Ventura River Watershed will help to avert even higher rate hikes in the future, which will occur if water purveyors are forced to purchase costly State Water to meet consumer demand. – Bren Study 2011

The Bren report concludes with;

Our final recommendations to watershed planners in the Ventura River Watershed are: 

(1) implement programs encouraging the increased installation of ocean friendly gardens and greywater systems in single-family homes,

(2) construct decentralized infiltration basins throughout the watershed, and

(3) increase CMWD and Meiners Oaks water rates to the state average.

Implementation of these strategies, coupled with responsible groundwater pumping, has the potential to increase water availability for human needs, improve ecosystem health, and improve water quality even in the face of climate change, land use change, and population growth.

Bren school project: Sustainable Water for the Ventura River Watershed

Alternatives developed:

Infrastructure Based Water Management Strategies


Infiltration Basins

Pervious Streets

Scalping Plant

San Antonio Spreading Grounds

Consumer Based Water Management Strategies

Ocean Friendly Gardens


Rate Increases to State Average

CMWD 33% Rate Increase

Pitfalls of the State Water Project:

Contrary to the advertised benefits, connecting to State Water potentially threatens to undermine the sustainability of the community that relies upon the Ventura River watershed. Full disclosure of the pitfalls of this strategy is required before the community becomes committed to higher rates for “paper water” that we may never receive.

Research continues to indicate that rising temperatures will result in changes in precipitation patterns, a significant decline in the Sierra snowpack, and early snow melt such that For the vast majority of potential future climate conditions, the State Water Project will have substantially more system shortages than what we’ve seen historically,” according to Dr. Geeta Persad, a senior climate scientist with the Climate and Energy Program at the Union of Concerned Scientists.

The California Water Impact network (C-WIN), a Santa Barbara based organization, published a 2017 report that demonstrates the cost impacts and consequences for State Water Project (SWP) participation to date, utilizing the experience of Santa Barbara County Coastal Aqueduct Project as an example of the statewide problem that will be encountered if the Twin Tunnels comes to fruition. The 'Santa Barbara Report' exposes the underlying problem of "paper water;" C-WIN spent three years gathering ... information through Public Records Act requests and Freedom of Information Act requests and found that consumptive water rights claims are at least 5 1⁄2 times more than available supply.

In a legal challenge against the City of Ventura’s State Water Interconnect Project, C-WIN states that:

The Interconnection Project is a major step backward from the growing recognition that local dependence on state water is a problem, not a solution, for water reliability and the environment. ...State water is so oversubscribed that the courts have identified more than half of its allocation as unreliable “paper water”.

The cost of state water will cripple Ventura’s ability to explore and develop sustainable regional solutions. ...Once a district is dependent upon the state water system, they’re responsible for the costs of the maintenance and new infrastructure of the entire SWP conveyance system. Ratepayers have no direct input and no ability to opt out of these maintenance and infrastructural decisions. The stated Ventura pipeline project estimate of $50 million does not include the exorbitant additional costs and risks of state water.

The EIR for the Interconnection Project evaded assessing the major impacts of growth encouraged by the false perception of state water availability. When the SWP predictably fails to ensure reliable deliveries, demands on other depleted sources such as groundwater, the Ventura River and Lake Casitas will only increase when it is too late to plan for integrated improvements in local water resilience.

These and other concerns voiced by the community regarding the long-term cost vs actual benefits indicate that State Water should be relegated to a “Conditional Strategy,” only coming into play if the local watershed-based strategy is not effective.

Conclusion and Recommendations:

The Draft CWRP provides an updated look at water supply and demand within the Casitas Municipal Water District service area. The new Safe Demand Policy provides a realistic assessment of the effectiveness of the WEAP action plan and community response to drought. This new perspective sheds light on the fact that the District is already achieving the newly prescribed Safe Demand which gives a 95% assurance that Lake Casitas will not drop below 20,000 AF of storage.

However, the report does not adequately acknowledge the need for greater coordination amongst the many agencies and individuals within the Ventura River Watershed. Groundwater provides a large proportion of the local water supply with Lake Casitas as backup, so integrated watershed management should be a priority. The community has shown a remarkable resiliency following the recent drought and fires, and the capacity for increased local water use efficiency should not be underestimated.

Based on the information provided in the Draft CWRP, CMWD has an opportunity to plan for local sustainability rather than develop the costly infrastructure for imported water. As recommended in the report, a full cost/benefit ($/AFY) analysis on a full range of alternatives should be conducted and management options should be prioritized by cost efficiency. The next step should be to develop a comprehensive water use efficiency and conservation policy and program to include:

  1. Integrated water budget for the entire Ventura River Watershed

  2. Coordination with partner agencies and the community

  3. Updated WEAP water allocations to comply with Sustainable Demand

  4. Increased water rates to a level that supports Sustainable Demand

  5. Support for watershed management programs to implement water efficiency and reuse, conservation, and groundwater infiltration and sustainable management

Casitas Water Reports:


Ventura River Watershed Management Plan, Walter, Ventura River Watershed Council, March 5, 2015. 

Sustainable Water Use in The Ventura River Watershed, Gardner et al, Bren School of Environmental Science and Management, University of California Santa Barbara, 2013

Climate change and the future of California’s water, Summary of presentation by Dr. Geeta Persad , Mavens Notebook, Nov 7, 2019

The Unaffordable and Destructive Twin Tunnels: Why the Santa Barbara Experience Matters, The California Water Impact Network, November 2017

On this Blog:

Casitas Water

Thursday, August 13, 2020

Retrospective on the Thomas Fire

The Ventura River has demonstrated amazing resiliency following the Thomas Fire.  The river appears healthier now than it has been in decades following the influx of sediment eroded from the mountains.  However, the initial flushes following the fire negatively impacted the river until the storms of 2019 "rolled" the bottom breaking up an impervious layer formed by ash and silt deposits.  The photos here are provided to illustrate what this looked like in the summer of 2018.

Ventura River, May 2020

Ventura River following the Thomas Fire, January 2018

Ventura River following the Thomas Fire, March 2018

The first storm immediately following the fire in January 2018 moved large amounts of black ash and very fine organic matter off the burnt hillsides. The second storm in March eroded additional fine sediments with a brown soil color.  These two events combined to form a hard crust on the stream bed.

The photos below from June 1, 2018 describe observations of this phenomenon. 

Ventura River 6-1-2018

The river bottom was embedded with ash and fine sediment that filled the voids and effectively "cemented" the cobble and gravel.  In the image above, a cobble was removed by hand to expose the layers below.  With no tools handy, it took considerable effort to loosen and remove this rock.

Ventura River 6-1-2018

Once a rock was removed, the hard crust could be broken up and pulled away by hand, further exposing the riverbed.  Here the substrate was agitated to allow the river flow to transport the fine sediments away.  The dark color of this plume indicates the organic ash eroded from the hillsides in the initial rain event.

Ventura River 6-1-2018

Removing a couple more rocks and agitating the surface eventually cleared this small area of river bottom.  The brown crust can be seen adhered to the rocks.  The image below provides an overview of the site.

Ventura River 6-1-2018

The upper Ventura River groundwater basin relies on flows infiltrating through the alluvium in the river reach downstream of the Robles Diversion.  The graphs below are from the monthly water update provided to customers of the Ventura River Water District.  This water district relies on wells in the Ventura River in the general vicinity of the photos above.  As noted at the time, groundwater levels did not  recover as normally expected in 2018.  However, the 2019 storms resulted in river flows that adequately cleaned out the river channel to allow recovered infiltration as illustrated by the 44 foot rise in groundwater in the bottom chart.  

Ventura River Water District, July 2018

Ventura River Water District, June 2019

On this blog:

March Rains - fires, flood, drought, and sand