Robles Diversion and Matilija Dam

Robles Diversion has been an essential component of the Matilija Dam Ecosystem Restoration Project (MDERP) since planning began in 2000.  

Background:

The Robles Diversion and Fish Passage Facility is located on the Ventura River 2.3 miles downstream of the Matilija Dam. The Facility includes a timber diversion dam and control gates to divert flows from the upper Ventura River for storage in Lake Casitas.  The lake serves as a primary and backup water supply for agricultural and municipal water users served by the Casitas Municipal Water District (CMWD).  

The diversion was originally constructed by the U.S. Bureau of Reclamation in 1956 as part of the Ventura River Project which is built around Casitas Dam and Reservoir, located on Coyote Creek about two miles above its junction with the Ventura River.  Casitas infrastructure also includes the 5.4-mile Robles-Casitas Canal, which conveys the diverted flow of the Ventura River into Lake Casitas; and the main conveyance system, which includes 34 miles of pipeline, five pumping stations, and six balancing reservoirs located throughout the project area.  When originally constructed Lake Casitas had a capacity of 254,000 acre-feet, but recent estimates have reduced this to approximately 237,000 acre-feet. 

Robles Diversion and canal
Jan 2003, Rich Reid

According to CMWD, Lake Casitas fills primarily from the natural flow of local creeks and the Robles Diversion. In any given year roughly 1/3 of the Lake’s water comes from the Robles Diversion. 

Diversions are limited by the size of the canal, which can only convey 500 cubic feet per second (cfs) and regulations in a NOAA biological opinion that require adequate releases of water to ensure fish passage and other downstream water supplies. 

The Coyote Creek watershed area that drains directly into the lake is only 3,500 acres. (In comparison, the similar sized Lake Cachuma (193,304 acre-feet) in the neighboring Santa Ynez watershed is supplied by more than 70 times the watershed area of 417 square miles (266,880 acres).)   It was this small watershed area that necessitated the addition of diversion from the Ventura River to help maintain the water supply in Lake Casitas. 

In 2005, a fish passage facility was constructed to allow migration upstream and downstream as well as to screen smolt and other small fish from being diverted into the lake. The components of this facility are shown below:

Robles Diversion components
source: Casitas Municipal Water District

Sedimentation Problems:

Robles Diversion - the flood filled the forebay with sediment and breached the timber cutoff wall
Casitas Municipal Water District quickly implemented emergency repairs to restore water
 diversions to Lake Casitas

As the Robles Diversion dam captures water for diversion in the large forebay, it also traps sediment.  This sedimentation requires ongoing maintenance, including the costly mechanical removal and transport of sediment following a series of small storms or, in some cases, one big winter.

In January 2023 the upper Ventura River experienced a 50-year flood with flows over 20,000 cfs in the Robles reach.  This occurred following the Thomas Fire of December 2017 which burned the majority of the upper watershed.  A huge volume of sediment, including cobble and boulders, backed up behind the diversion dam filling the forebay.  Flows became diverted to the east, eroding the earthen berm up until, fortunately, the timber wall failed.   A similar event occurred in 1969, when 100-year flood flows were diverted both east and west (a phenomenon known as "avulsion") damaging both the diversion canal and the adjacent "riverbottom" neighborhood of Meiners Oaks.  Diversion capability was not restored for the remainder of 1969.

As described in Matilija Dam: removal plans and sediment transport, this existing sedimentation problem will become worse as sand, gravel, and cobble begin to pass over the dam.  Even if Matilija Dam remained in place, future equilibrium sediment loads will triple from what Robles has experienced over the past 70 years.  And dam removal will create a short term sediment "wave" that could also overwhelm the facility.

Solutions to increased sedimentation:

The 2004 Army Corps of Engineers feasibility study for dam removal included a "High Flow Sediment Bypass" at Robles Diversion.  This bypass consisted of additional gates that could be opened to allow sediment transported during peak flows to be flushed through this reach of the river, preventing the kind of backup that occurred in 2023.  

 

In 2019, the Robles Working Group was formed to aid planning and implementation of modifications to the Robles Diversion Facility (operational and/or physical) as an essential component of the Matilija Dam Ecosystem Restoration Project (MDERP).  A consulting team is facilitating and providing technical support for the RWG. The RWG is currently focused on evaluating and selecting an alternative for the Robles Diversion Facility that will enable it to function reliably for water supply, sediment passage, and fish passage.

This work has determined that 

• Existing bypass is too narrow, less than 30% of natural river channel

• Matching natural river width at Robles would require additional bypass between 130 ft to 160 ft wide. 

• It’s feasible to increase flow and sediment transport capacity at Robles

• Possible to adjust flow split between existing bypass and additional bypass as desired

by modifying invert elevation and forebay layout

• Various options to locate additional bypass and change approach flow conditions by

modifying forebay (narrowing, straightening, splitting)

Several alternatives were considered and narrowed down based on additional computer analysis.  Currently the Bureau of Reclamation has built a physical scale model in their facility in Denver to test various configurations and determine the best approach for optimum sediment management.

The two primary alternatives #3 and #5 are illustrated below:

Fisheries considerations:

Although the initial intent of the Robles Diversion modification effort was to address the sedimentation concerns experienced during high flows, the resource agencies have a strong interest in improving fish passage around the diversion facility.  Currently the fish ladder is the only opportunity for passage, even during times when the diversion is not operating.  All river flows are currently routed through the diversion facility down the fish ladder with no bypass option, even outside the diversion season.  And although the fish ladder has proven to be effective for trout, there is interest in ensuring other native species can pass.  Additionally, the current operations are governed by NOAA's biological opinion, which defines how much water is allocated to the fish passage operations.  All of this adds considerable complexity to an already difficult engineering task.   Considerable resources are being directed to the exploration of additional fish ramps or other passage facilities to resolve these concerns.

Flooding concerns:

The original Corps of Engineers plan for this reach included construction of a new levee extending downstream from the Robles Diversion.  This was based on coarse 1-dimensional flood modeling that predicted an incremental increase in streambed elevation due to dam removal.  

Apart from the huge construction footprint, local residents did not welcome the prospect of a large wall complete with chain link fences, rodent control, and service road in their back yards.  It turns out much of the flood concern was based on unrealistic backflow from the Ventura River.

Subsequent 2D modeling provided a more realistic understanding of the flood concerns at Meiners Oaks.  As described above, sediment trapped by the Robles diversion dam creates a flood hazard to the adjacent community when the river is diverted by the blockage (avulsion.)  The consulting team has conducted a preliminary study of how these high flow bypass designs will affect the downstream flood risk.  Although the existing flood risk from the Ventura River may be characterized as relatively minor overtopping of the naturalized embankment, initial assessment shows that enhancing the flow path through this reach will help reduce this potential flooding.  (Note that a considerable area of this neighborhood is at risk from overflow from Cozy Del creek, shown in yellow.)  These preliminary results are promising, although the primary flood risk is potential stream bank erosion on the left (east) bank of the existing high flow channel downstream of the Robles Diversion.  This downstream reach is directly affected by how flows are directed by the upstream modifications. 

Summary:

The Ventura River Project constructed in 1959 provided Casitas Municipal Water District more than the 50 year lifespan of benefits from Matilija Dam.  Over that period, the district was able to release water stored in Matilija reservoir for diversion at Robles into Lake Casitas.  Sedimentation has rendered Matilija Dam completely useless for water supply, and structural degradation requires its timely removal.  Most importantly, dam removal necessitates modernization of downstream infrastructure. 

Modification of the Robles Diversion facility has been identified as the critical path component of the Matilija Dam project.  Although complex and expensive, careful consideration of a solution that eliminates costly maintenance and periodic cleanout of sediment from the diversion facility as well as the need for costly maintenance of a permanent levee downstream will provide long term benefits to the community.  Completing this component will clear the path to dam removal which is necessary to restore watershed resilience including access to headwater habitat that the endangered steelhead require.  

References:

https://matilijadam.venturacounty.gov/robles-diversion/

https://www.casitaswater.org/learn-about-diversions

https://www.venturariver.org/2023/02/january-2023-flood-overview.html

Elwah steelhead success story

More good news from the Elwah River...  An article in Northwest Sportsman reveals the incredible resilience of the steelhead which have rebounded faster than predicted following the removal of two dams on the Elwah River in Washington State.  The video, "Rising from the Ashes" tells the story from the perspective of the dedicated biologists and volunteers who have undertaken annual snorkel surveys on the remote and hard to access river in the wilderness of the Olympic National Park.

The rapid recovery of the summer steelhead on the Elwah demonstrate the value of resident rainbow trout above dams.  Given the chance, even after 100 years with no possibility of returning from the ocean, these fish can make a comeback.

This is real world confirmation of the hope for recovering the endangered southern steelhead populations blocked by Matilija Dam.  With no human intervention, other than just getting out of the way, we can realize a rapid recovery of the native fish and the ecosystem on which we all rely.




New Film Highlights Elwha Summer-runs ‘Rising From The Ashes’, Northwest Sportsman, April 23, 2020

On this blog: steelhead

Ecosystem flows

Natural flows in rivers throughout the American West have been significantly disrupted by dams and diversions, groundwater extraction, land use changes, and other human influences.  Over time this has led to the decline of freshwater ecosystems to the point that many species have become endangered.  For instance, rivers rely on natural floods for maintenance of the river channel and floodplain, and flow of critical nutrients and biota.  Large dams mute or eliminate downstream flooding (winter flood pulses) by capturing these flows in a reservoir.  Similarly most western rivers are drying up during the dry months (summer/early fall base flows), an increasing concern with more frequent drought and heat due to climate change, and the primary concern on the Ventura River.

Functional Flows, figure from "A Path Forward for California's Fresh Water Ecosystems", PPIC 2019

The diagram shown here illustrates alterations to the natural flow regime throughout the year and a proposed "Functional flow regime."  The aim of functional flows is to re-establish some of the basic river functions in highly modified systems to restore ecosystem function.

The question is how to develop a management paradigm to allocate water to functional flows and ecosystem health?

A recent report by the Public Policy Institute of California presents the case for Ecosystem Based Management as a solution to California's water problems.  Maven's Notebook presents an excellent summary of recent discussions along with the technical references.

In particular, this report concludes that the current management focus on endangered species is failing, and we need a more holistic approach:

Ecosystem-based management emphasizes the simultaneous management of water, land, and species to improve ecosystem condition for native biodiversity and human uses. It shifts the management emphasis to the social, economic, and environmental benefits that come from healthy ecosystems, rather than narrowly focusing on mitigating harm to protected species.

Sustainable watershed management plans, backed by binding comprehensive agreements, are the best way to accomplish ecosystem-based management. These agreements can be adopted by state and federal regulators to meet Clean Water Act and ESA requirements and can align other agency priorities and actions.

With ecosystem-based management, there are a suite of actions available.  The first is to establish an ecosystem water budget that is an allocation of water for the environment that functions much like a senior water right that can store, trade, and flexibly allocate that water to respond to changing conditions.

An outline of this management approach is presented in the PPIC Policy Recommendations:

Promote inclusive planning and governance

• Identify the desired ecosystem condition
• Establish metrics
• Provide strong scientific support
• Set up transparent governance
• Ensure reliable funding

Employ multiple ecosystem management tools

• Establish ecosystem water budgets
• Employ functional flows
• Manage native and non-native species
• Manage at the appropriate scale

Encourage sustainable watershed management plans

• Align agency actions
• Promote comprehensive agreements
• Set timelines and backstops
• Update water quality control plans
• Incentivize or mandate plans

It is important to highlight the differences between ecosystem-based management and other, often similar approaches. For example, 

      * ecosystem management seeks to manage the ecosystem for species conservation goals and objectives, such as resilient populations of native plants and animals. This is accomplished principally by constraining land and water use and often uses recovery of protected species as a primary objective. In contrast, 

      * ecosystem-based management integrates human uses into the setting of conservation goals and objectives, balancing the uses of the resource. Ecosystem-based management also differs from 

      * Integrated Water Resources Management (IWRM), which focuses principally on coordination and funding of local water management projects while managing their impacts on ecosystems.


Renewed discussion of Ecosystem-based Management supports the vision presented in the Ventura River Ecosystem blog.  This approach applies readily to the Ventura River Watershed, especially with ongoing planning for this priority basin under SGMA.  The Sustainable Groundwater Management Act provides for self-organized groundwater sustainability agencies (GSAs) and required groundwater sustainability plans.  However, in our case the Ventura River would ideally combine the two existing GSA's into a single watershed-based agency to better realize the Ecosystem-based management approach.

On this blog:

Ventura River; Ecosystem-based Management

Reference:

text in italics above quoted from: 

Mavens Notebook: Ecosystem-based Management: A New Paradigm for Managing California's Freshwater Ecosystems

A Path Forward for California’s Freshwater Ecosystems, PPIC Water Policy Center, December 2019

• PPIC Policy Recommendations

More information:

TED GRANTHAM: THE EVOLUTION OF ENVIRONMENTAL FLOWS IN CALIFORNIA

March rains

March storm moves over the Ojai Valley. This thunderstorm produced a brief period of hail.

After, a record dry January and February, the rains returned in March.  Perhaps not the "March miracle" of the past, but certainly appreciated given the potential for an otherwise very dry year.  At 13" for the season, Ojai is still way below the 23" average rainfall, but it looks like a wet spring ahead.

28 day Rainfall Map, March 2020

The storm of March 11 delivered almost 5 inches at Old Man Mountain, which typically registers the highest rainfall in the region.  Old Man Mountain lies at the headwaters of Matilija Creek, resulting in quickly rising waters during a downpour.  

24 hour rainfall, March 16, 2020

The hydrograph below shows flows in the river for the month of March at Matilija Creek and Foster Park.  The March 16th rain event resulted in peak flows for the season.

Ventura River above Hwy 150,  5pm
March 16, 2020

Ventura River at Santa Ana bridge,  6pm
March 16, 2020

This short burst of energy in the river moved significant amounts of sand and gravel sized sediment downstream.  In addition to visible deposition in Matilija reservoir, sedimentation was evident at Robles diversion and the reach downstream in the Ventura River Preserve.   Gravel is an important habitat consideration for the endangered steelhead, which lay eggs in "redds", or pockets formed in the gravel.  The effects of the Thomas Fire continue to be evident as the river transports sediment eroded from the mountains downstream, to the benefit of riverine habitat. 

Robles Diversion dam, March 19, 2020

Ventura River downstream of Robles Diversion, gravel bars, March 19, 2020

Ventura River Preserve, March 21, 2020

Ventura River Preserve, April 1, 2020

Flows in the river were also translated into rising groundwater at the Ventura River Water District wells and increased storage in Lake Casitas.

Water Supply, Courtesy of Ventura River Water District
April 1, 2020

At time of writing the watershed is preparing for another potentially significant storm and more rainfall for the week of April 5.


On this blog:
Matilija Reservoir March 2020
Steelhead spawning surveys
Thomas Fire


Reference:
Ventura County Rainfall map
Casitas Municipal Water District
Ventura River Water District

Letter: Santa Clara River Estuary

January 16, 2018

Gina Dorrington
Ventura Water
501 Poli Street, Room 120 Ventura, CA 93002
via email: gdorrington@venturawater.net

RE: SCRE Special Studies – Water Recycling Opportunity

Dear Ms. Dorrington:

The Ventura County Chapter of the Surfrider Foundation has voiced concerns with water quality at the mouth of the Santa Clara River since our Blue Water Task Force identified high bacteria levels at this popular surfing location in the early 1990’s. Recognizing the benefits of integrated water management, the Surfrider Foundation has been a longtime proponent of recycled wastewater to enhance our coastal ecosystems. Wastewater discharges have historically impaired coastal water quality, and even with advances in technology, increased nutrient levels impact receiving waters.

We would like to re-state our support for 100% recycling of the city’s wastewater to eliminate the discharge into the Santa Clara River Estuary.

We do not concur with the analysis presented at the November stakeholder meeting that oversimplify the ecosystem associated with the Santa Clara River Estuary (SCRE.) Indeed, as other commenters have noted, this system is in fact much more representative of a coastal lagoon, since it does not maintain a perennial opening to the ocean. Indeed, it is this fact that creates the problems with the wastewater discharge. Without a regular exchange between the lagoon and the ocean, nutrient rich wastewater accumulates in an unnatural manner behind the beach berm. Only during large winter storm events or human intervention does this lagoon breach. This results in unnaturally high water levels and poor water quality.

Finding of Enhancement is Flawed:

Any conclusion that determines that the lagoon is enhanced by the wastewater discharge are flawed. Although the resource agencies rightly are concerned for the endangered and special status species that rely on habitat at the mouth of the Santa Clara River, current conditions limit, rather than support those species. The unnaturally high water levels resulting from the discharge create a simplified pond habitat that is subject to episodic draining. Sea water exchange, a necessary part of this ecosystem, is also precluded with the flooded lagoon. The elimination of habitat complexity and poor water quality has created an ideal habitat for non-native species, most prominently carp. From our experience on the Ventura River, carp are the predominant fresh water species below the Ojai Sanitary District discharge on the lower Ventura River, relegating this reach to migratory status for the endangered Southern Steelhead. Steelhead may survive in such an environment, but they certainly wouldn’t choose it.

An Opportunity for Ecosystem Benefits:

A more complete ecosystem view of the situation has not been conducted as part of the SCRE analysis. By focusing exhaustively and exclusively on the Santa Clara River Estuary, the potential benefits of eliminating the wastewater discharge have not been fully considered. Consider this fact:

50% or more of the discharge originates from the Ventura River

The City of Ventura relies on a wellfield at Foster Park and surface storage from Lake Casitas for more than half the water supply. Both of these sources are currently stressed from over allocation during the prolonged drought.

How could a point source discharge directly into the Santa Clara River Estuary be considered to mimic “natural” processes and enhance the habitat, when much of the water originates from the adjacent watershed?

Most significantly, studies have documented the high quality spawning, rearing, and refugia habitat in the Ventura River upstream of the Foster Park wellfield. However, flows in this reach have become seriously impaired by over-extraction of groundwater, to the point that in recent years this refugia habitat has dried up for extended periods during the critical summer and fall months. It should be noted that this reach of the Ventura River was historically known as the “live reach,” for the rising groundwater in the vicinity of Casitas Springs, which was also named for this phenomenon. These are precisely the conditions that favor native species such as the southern steelhead. Indeed, recent population surveys have documented the presence of native trout in this reach.

Water Budget Perspective:

Consider the potential benefits from developing a “new” supply from recycled water. These slightly outdated supply and demand numbers are taken from the City's 2013 Final Comprehensive Water Resources Report. It is evident from this graph that if 'new' sources of water are not found the city will outgrow its water supply in the near future.

The red arrow shows that the potential for recycled water in Ventura is close to 50% of demand. (Of course the actual volume would be less than this depending on treatment and reuse options, but this demonstrates the overall magnitude.) Therefore water recycling would provide an opportunity to eliminate the flooding problem at McGrath as well as offset municipal water demand (i.e. an 'integrated solution'.) This demand offset could provide an opportunity to reduce pumping at the Foster Park wellfield during dry months of the year to sustain the critical habitat within the “live reach” of the Ventura River.

Recommendation:

We encourage the City of Ventura and the stakeholder resource agencies to carefully reconsider the potential benefit from maximizing the recycled water potential. Rather than choosing to maintain an artificial pool at the Santa Clara River Estuary, which has very limited habitat benefits, demand offsets gained through recycling 100% of the wastewater effluent may be applied to the enhancement of the comparatively high quality habitat in the Ventura River. In turn, the coastal lagoon will return to a more natural hydrology with improved water quality and habitat, while also eliminating the non-native habitat conditions that are currently degrading the SCRE ecosystem.

Sincerely,

A. Paul Jenkin, M.S.
Ventura Campaign Coordinator, Surfrider Foundation (805) 205-4953 pjenkin@surfrider.org

cc: SCRE Stakeholder e-mail list 

References:
Steelhead Population and Habitat Assessment in the Ventura River / Matilija Creek Basin 2006-2012 FINAL REPORT

Ventura River Ecosystem - wastewater, VenturaRiver.org 

Ventura River - Instream Flow program

The Ventura River has been identified as one of five priority streams in the California Water Action Plan (WAP.)  The State Water Board and CDFW are currently working to identify potential actions that may be taken to enhance and establish instream flow for anadromous fish in these five priority streams.

http://www.waterboards.ca.gov/waterrights/water_issues/programs/instream_flows/cwap_enhancing/

The streams identified for the WAP effort are primarily coastal streams where the survival of salmon and steelhead (together referred to as salmonids) are of particular concern. Of the 22 distinct groups of anadromous salmon and steelhead in California, 13 (59%) are in danger of extinction and are in need of enhanced protection.

The Ventura River provides an opportunity to advance state water management policy by integrating groundwater and surface water management for the first time.  On March 28, 2016, a team representing the State and Regional Water Resources Control Board and California Department of Fish and Wildlife toured the watershed.

Instream flow team at Robles Diversion fish passage

More info:  State Water Resources Control Board
                   California Department of Fish and Wildlife

On this blog: http://www.venturariver.org/search/label/groundwater

Recovering Ventura River Steelhead

An article titled 'Recovering Ventura River Steelhead' was published in May 2012 issue of The Osprey, a Journal Published by the Steelhead Committee of the Federation of Fly Fishers. It provides an overview of the history and current state of steelhead recovery efforts in the Ventura River. 

The article may be downloaded here http://www.ospreysteelhead.org/archives/TheOspreyIssue72.pdf

The Osprey archives: http://www.ospreysteelhead.org 

McGrath State Beach flooding

This year's drought combined with the constant artificial flow into the Santa Clara River estuary have resulted in a flooded campground at McGrath State Beach.  As documented by the ongoing studies, up to 9 million gallons per day currently discharged from the City of Ventura's wastewater treatment plant create artificially high water levels in the coastal lagoon.  Winter floods naturally breach the lagoon, which then takes months to re-fill, but without significant river flows the sand berm keeps the rivermouth closed.  In 2010 an artificial breach resulted in rapid draining of the lagoon and death of steelhead trout and other endangered species.  (see Estuary breach kills fish)

photo: VCStar.com

This is just one symptom of a complex water management issue that begins at the Ventura River - this year the river has dried up at Foster Park, one of the the city's primary water supplies.  This water is piped to homes and businesses in the city, used once, and discarded as 'wastewater' which is treated and discharged into the Santa Clara River.  We continue to advocate for 'Integrated Water Management' that would increase water use efficiency though conservation and decentralized re-use.

Surfrider submitted written comments on February 28, 2013 that included this statement:

The Surfrider Foundation’s national ‘Know Your H2O’ campaign recognizes the importance of integrated water management as a solution to coastal problems. Many municipalities are responding to the global water crisis through the implementation of water recycling to diversify their water supplies. The SCRE Phase 2 study does an excellent job of identifying opportunities for wastewater reuse throughout the City of Ventura, and has identified a number of projects that may become components of an integrated water management strategy.

As we have commented previously, it is important to recognize that, on average, two thirds of the water discharged into the Santa Clara River Estuary comes from the Ventura River. The report notes that the city’s water supply is stretched thin, and this is evidenced in the current drought that has dried up the Ventura River, including the City’s wellfield at Foster Park. Cumulative impacts within the Ventura River have resulted in a 303d impairment listing for pumping and diversion. Therefore, a watershed-based strategy designed to restore instream resources and protect groundwater basins is essential to addressing multiple regulatory pressures and to ensure the long-term viability of the city’s water supply.
We agree with the general consensus from the stakeholder workshop that implementing Indirect Potable Reuse (IPR) and Direct Potable Reuse (DPR) within the City of Ventura is the highest and best use of the city’s wastewater. As discussed in the report, the Ventura River provides higher quality water than the groundwater on the East side. Therefore there is some merit to keeping Ventura River water within that watershed as proposed with the North side decentralized treatment plant. We also recommend that an East side decentralized wastewater treatment plant remain as a possible alternative in this strategy. This plant should be included in planning for urban expansion on the east side because treating and reusing water nearer its source would provide other long-term benefits. For instance, the location of the existing treatment plant within the floodplain of the Santa Clara River and an area of potential sea level rise inundation makes it vulnerable to catastrophic events that may require its relocation within the 50- to 100-year time frame. A citywide decentralized water reclamation system would reduce this vulnerability and limit the potential impacts from future flooding while increasing overall water use efficiency. 

...To summarize, we strongly support an expanded water-recycling program within the City of Ventura, but disagree with the analysis of habitat enhancement from the wastewater discharge into the Santa Clara Estuary. We encourage the City to continue to develop an integrated water management plan that considers the broader long-term benefits of increased water use efficiency.



In the news:
     mcgrath-state-beach-campground-flooded-closed
     A no-win situation in the McGrath State Beach flooding

More info: SCRE Special Studies - http://www.cityofventura.net/rivers

On this blog: http://www.venturariver.org/search/label/wastewater

Surfrider comment letter:  https://dl.dropboxusercontent.com/u/39386757/SCRE%20Studies%20Surfrider%20comments%20Feb-2013.pdf

..

Pumping and Diversion TMDL

One of the major issues currently facing the Ventura River is 'pumping and diversion'.  The river has been listed by the State Water Resources Control Board as 'impaired' in Reaches 3 and 4 due to excessive water diversion.  The water board is now considering developing a TMDL, or 'Total Maximum Daily Load', for this impairment.  The alternative is a MOA (Memorandum of Agreement) and plan of action for local water agencies to cooperate on a groundwater management plan.

Diversion of surface flows occurs at the Robles Diversion Dam (Reach 4) and at Foster Park (Reach 3) as well as smaller private diversions.  Pumping occurs at numerous wells that extract water from the shallow aquifers that are connected to surface flows.  In both cases, the amount of water flowing in the river is diminished, impairing ecological function.  For example, low flows become a problem when combined with excessive algae growth - this reduces dissolved oxygen levels that aquatic life depends upon.  (See Algae: problem or symptom?)

Pumping water from wells during dry summer months may cause pools to rapidly dry up, stranding and killing native steelhead trout and other aquatic species.  Although this often goes unseen (they become fodder for predators such as herons, racoons, etc.), fisheries managers in past years have responded by relocated fish from drying pools.

Pumping and Diversion has been discussed during several of the recent watershed council meetings, along with presentations about water rights and the effects of wells on surface flows.  As one would expect, there is controversy surrounding the cause and effect, and some even question if there is reason for the impairment listing.

In order to illustrate the problem, Santa Barbara ChannelKeeper produced this video:



The timelapse sequence in this video and the pressure logger illustrate the rapid filling and drying of a pool on the Ventura River Preserve.  Because this occurs independently of time of day it suggests that something other than natural evapotranspiration is occurring to impact surface flows in the river.

To illustrate the issue, local groundwater professional Jordan Kear has provided presentations to the Watershed Council. These graphics are from Surface & Groundwater Interaction Study, Kear 7-17-12

The main stem of the Ventura River is divided into two groundwater basins, with the division occurring at Foster Park.

To understand what happens to surface flow, one must understand how the stream interacts with groundwater.  A stream may be 'gaining' or 'losing' depending upon the level of the water table beneath and adjacent to the river channel.  And when the water table drops far enough the stream becomes 'disconnected.' 

One of the areas in question is Reach 4, the section of river downstream of the Robles Diversion  within the upper Ventura River groundwater basin.  As the figure below illustrates, this 'Robles Reach' is usually a 'losing stream,' which often becomes 'disconnected' in dry periods. 

Then, as river flows increase during winter months and the groundwater basin fills back up, and surface flows re-establish.  (In extremely wet periods it may also become a 'gaining stream')

Surface water (dotted line) and Groundwater (solid blue line) interaction
 in the Robles Reach of the Ventura River  (Kear Groundwater)

Although this Surface & Groundwater Interaction Study concluded that "pumping of wells has a relatively minor effect on river flow," this was based upon an experiment that revealed the Meiners Oaks Water District wells reduced river flows by up to 1.5 cfs (cubic feet per second.)  However, this conclusion does not take into account the cumulative effects of multiple wells pumping from the same groundwater basin when summer inflows from Matilija Creek may only be 5-10 cfs or less.

 Reach 4 - Wells within 1000 ft of Ventura River

What this study does demonstrate is that there is some direct interaction between groundwater pumping and surface flows.  What is less clear is the effect from wells farther from the river, but within the larger Upper Ventura River groundwater basin.

Wells within the Upper and Lower Ventura groundwater basins

Last year, a first cut at developing a water budget for the two groundwater basins was presented with the Upper and Lower Ventura River Basin Groundwater Budget.  (The first draft of this analysis suggested an overdraft of 3,240 acre-feet per year, before Lake Casitas storage/supply was added.)

Reach 3 is under similar stress, as the City of Ventura has recently constructed new wells at Foster Park.  Although these wells are regulated by NOAA Fisheries, who have established minimum flow criteria, this reach is influenced by other extractions which have cumulative effects on surface flows.

Although this is clearly a difficult issue, the TMDL listing has brought many of the major water suppliers and users together to potentially work cooperatively on a groundwater management plan.

It is important to understand that this is not only about endangered species and recreation, which are protected under the Clean Water Act, but most importantly the future sustainability of our communities, including over 100,000 residents in Ojai and Ventura:

• Our communities depend almost entirely on the Ventura River for water supply
• In recent years, expansion of agriculture as well as planned urban development are increasing pressure on this limited resource
• New wells are being constructed, increasing groundwater pumping
• Currently there is no coordinated oversight of groundwater resources on the main stem of the Ventura River
• We are clearly at, or above, the maximum sustainable water extraction from the Ventura River

More info:

Pumping and Diversion Fact Sheet

A Really Short Course on Water Rights, Birosik 6-13-12

Surface & Groundwater Interaction Study, Kear 7-17-12 (2.8 Mb)

Upper and Lower VRB GW Budget and Management Presentation 05-25-2010 (3.4 Mb)

Upper and Lower Ventura River Basin Groundwater Budget and Management Plan (18 Mb)


See also:

http://www.venturariver.org/search/label/groundwater

http://venturawatershed.org/presentations

http://friendsofventurariver.org/document/?cat=Ground%20Water

http://venturawatershed.org/past-meetings


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Quarry appeal denied

On Thursday May 23 the Ventura County Planning Commission denied an appeal by Stop the Trucks! 

The question was whether the April 17 decision to approve the Ojai Quarry's Reclamation Plan and expanded operations was made without adequate environmental review.  

The commission heard several hours of testimony reasoning that "a significant change" had occurred since the quarry's original Conditional Use Permit was approved in 1995.  Evidence presented included the ChannelKeeper video illustrating the impact of fine sediment discharge from the quarry on steelhead spawning 'redds' directly downstream of the quarry.  In 1997 the Southern Steelhead was listed under the federal Endangered Species Act.

Ojai Stop the Trucks also provided an independent review of the quarry's amended Reclamation Plan, stating that the plan is flawed and inaccurate.

The hearing ran from 8:30 am until 4:30 pm, at which time the County Planning Commissioners voted 4-1 that  the evidence submitted did not convince them that these impacts are "SIGNIFICANT" under CEQA law.

More info: 

Ventura County Planning Commission:  http://www.ventura.org/rma/planning/MA/pc.html

Blog archive:  Ojai Quarry

Stop the Trucks: http://www.ojaipost.com/tag/stop_the_trucks/

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Ojai Quarry expects to be back in business

At the Febuary 23 Planning Commission Hearing county regulators vowed to get the Ojai Quarry back up and running.  The commission continued the revocation hearing until May 24 while the state conducts its review and county staff tie up loose ends. According to the newspaper, Planning Director Kim Prillhart said "I couldn't be happier with that," and hugged Mosler after the hearing.

The California Office of Mine Reclamation (OMR) stepped in after the Ventura County Planning Commission had decided to wait until Febuary 23, 2012 to make a decision.  Although the County is giving Mosler two months to try to reach a compromise with County planners, the Ojai Quarry was removed from the state list of approved mines.  This put County projects on hold, as Matilija rock destined for Callegus Creek was deemed ineligible for public contract.

Meanwhile, steelhead and water quality continue to be impacted by runoff from the quarry.  Erosion of the steep slope during rain events delivers fine sediment to the creek, which settles out downstream.  During a recent survey, several inches of silt could be seen covering the gravel bottom.  Steelhead spawning 'redds' have been documented in this reach of North Fork Matilija Creek, and the influx of silt can smother eggs and alvein that rely upon the oxygen rich water flowing through the spawning gravel.

Steelhead spawning redd in North Fork Matilija Creek, March 21, 2012

Steelhead eggs,  North Fork Matilija Creek, March 21, 2012 

In the news: 

October 27, 2011:        County proposes to shut Ojai mine after owner refuses to pay up 

December 13, 2011:    Mosler quarry heads for showdown before county Planning Commission 

December 15, 2011:    Ventura County Planning Commission delays decision on quarry near Ojai

January 10, 2012:        State deals business blow to Ojai Quarry

February 20, 2012:     Regulators, quarry operator moving toward deal 

February 23, 2012:    In Ojai, quarry owner expects to be back in business  

More info:  http://www.venturariver.org/search/label/Ojai%20Quarry
Stop the Trucks Coalition:  http://www.ojaipost.com/tag/stop_the_trucks/