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Ryan J. Mahoney*
Ryan John Mahoney, JD ‘17, LLM ‘17, McGeorge School of Law, is staff counsel with the California Office of Environmental Health Hazard Assessment. Mr. Mahoney’s article won the 2018 California Water Law Writing Prize, awarded at the 2018 California Water Law Symposium.
INTRODUCTION
Sedimentation of reservoirs is a threat to California’s water supply, water quality, public safety, and environmental health.[1] The accrual of sedimentation reduces reservoir storage capacity, causes heavy concentration of toxic materials on the floor of the reservoir, and directly affects water supply reliability, reservoir infrastructure, and ecosystems reliant on the waterway on which the reservoir is constructed.[2] California cannot continue to do so little to address the problem of sedimentation of its reservoirs.[3] Water is essential to California’s stability, success, and prosperity, and without a sufficient and reliable water supply California is in danger of suffering social, economic, and environmental hardship.[4]
California should adopt new laws that require reservoir owners and operators take specific actions to prevent, eliminate, and reverse sedimentation in existing and future reservoirs.[5] Developing laws to regulate sedimentation will be a complex endeavor that must involve significant public investment and stakeholder input through public workshops, meetings, and hearings. However, the loss of water storage capacity and potential threats to dam operation and structural integrity caused by sedimentation should not be permitted to occur in California’s aging dam and reservoir infrastructure. Within the next several decades many of California’s reservoirs will approach the end of their anticipated design lifetime, while many others have already passed their anticipated design lifetime.[6] Many of these reservoirs are vital parts of California’s water infrastructure; thus, California must act now to address sedimentation because sedimentation is causing, and will continue to cause, significant decreases in reservoir storage capacity and can detrimentally impact both the operation and structural integrity of the dam.
WHAT IS RESERVOIR SEDIMENTATION?
The Process of Sedimentation
Sedimentation is a process by which the bottom of a reservoir fills with large and small sediments transported into the reservoir by water.[7] Dams impede the flow of water allowing sediments suspended in, moved by, or dissolved in water to settle and fall to the reservoir floor.[8] Sediments on the reservoir floor accumulate and form layers of sediment building on top of one another creating highly compacted sedimentation.[9] Highly compacted sedimentation forms, because coarse sediments settle down on the reservoir floor leaving gaps that are filled by small grain sediments.[10] Essentially, sedimentation in a process that occurs when dirt and debris enter a reservoir, are trapped by the reservoir dam, and fall to the reservoir floor becoming tightly compacted.[11]
Sedimentation – Natural or Influenced by Human Conduct?
In a water system without human influence sedimentation is a natural process in streams, rivers, and lakes.[12] However, most water systems are influenced by human conduct, usually in a multitude of ways, two of the most common of which are dams and reservoirs.[13] Dams and reservoirs create sedimentation not found in a waterway uninfluenced by human activity, because dams prevent significant portions of sediment from exiting the reservoir and flowing downstream to the rest of the watershed.[14][15] Additionally, many of the most significant factors impacting sedimentation are caused by human conduct, including, but not limited to: (1) the amount of sediment produced in a watershed; (2) the reservoir’s age and condition; (3) the efficiency at which a reservoir traps sediment; and (4) the amount of sediment “trapped by other dams in the watershed.”[16] Thus, sedimentation is a natural process, but dams, reservoirs, and other human activities influence where, where, and how sedimentation occurs.[17]
WHY SEDIMENTATION OF RESERVOIRS IN CALIFORNIA MATTERS?
Detrimental Impacts of Sedimentation in Reservoirs
Water Supply, Water Quality, and Toxic Contamination
Sedimentation detrimentally impacts water supply, because it reduces reservoir storage capacity as sediments accumulate at the floor of the reservoir causing the floor of the reservoir to rise in elevation.[18] The amount of water supply impacted by sedimentation depends on factors, including, but not limited to: the depth of the reservoir, the capacity of the reservoir, the rate at which sediments enter the reservoir, and upstream influences.[19] Water quality is impacted by sedimentation, because sedimentation causes the concentration of toxic chemicals, pesticide residues, and heavy metals on the reservoir floor contaminating the water and complicating sedimentation removal strategies.[20] No reservoir is immune from the impacts of sedimentation, all are detrimentally impacted in some form or fashion, most commonly in the areas of water supply and water quality.[21]
Reservoir Infrastructure and Economic Impact
Infrastructure is detrimentally impacted by sedimentation, because sedimentation can impede the physical operation of the reservoir’s dam by causing damage to a dam’s turbines or water release outlets.[22] Additionally, sedimentation adds to the pressure and weight dams must be capable of sustaining because sedimentation pushes against dams creating a significant force.[23] Economic concerns arise with sedimentation, because sedimentation reduces water supply detrimentally impacting the economy, causes toxic contamination requiring water sanitation, and results in the need for prevention and removal projects.[24] Some of the economic concerns most prevalent include, but are not limited to, cost benefit analyses of: methods designed to avoid sediments from entering reservoirs; sedimentation removal through dredging or sluicing projects; and reservoir expansion after the water storage capacity of the reservoir dips below a specified level.[25] Thus, sedimentation detrimentally impacts reservoir infrastructure and causes economic concerns that are unavoidable and difficult to mitigate without a proper sedimentation strategy.[26]
Detrimental Effects on Ecosystems
Toxic Sedimentation
Sedimentation affects aquatic and terrestrial ecosystems in a multitude of ways, including ecosystems within the reservoir and those downstream.[27] High concentrations of toxic chemicals, pesticide residues, and heavy metals trapped by reservoirs cause harm to ecosystems within reservoirs, because they negatively impact both the quality of the water supply and the health of plants and animals in the reservoir.[28] Downstream ecosystems are impacted by sedimentation, because sedimentation is sometimes released from reservoir causing sediments that have high levels of toxic contaminants to enter the ecosystem with very little water for dilution.[29] Therefore, concentrations of toxins in sedimentation result in harm to ecosystems within and downstream of reservoirs, because dams trap toxic materials causing high levels toxic sedimentation on the reservoir floor.[30]
Downstream Erosion
Sedimentation harms downstream ecosystems, because it results in less replenishment of soil and rock.[31] Reduced replenishment of sediment causes increases to erosion to downstream rivers, creeks, and streams, because rivers, creeks, and streams lose sediment as water travels downstream and reservoir sedimentation prevents rejuvenation.[32] Furthermore, bank and floor erosion cause rivers, creeks, and streams to become straighter, deeper, and wider after an upstream reservoir is constructed causing less habitat for fish and wildlife, as well as the loss of economically valuable riparian land.[33] Thus, sedimentation causes downstream erosion resulting in a number of harms to public safety and downstream ecosystems.[34]
Sedimentation Releases (Sluicing)
Sluicing detrimentally affects ecosystems in reservoirs and those downstream, because sluicing is the physical release of sediments that have accumulated on the reservoir floor.[35] Sluicing results in the contamination of much of the water due to the toxic materials in the sediment sluiced.[36] Sluicing causes the release of toxic chemicals, pesticide residues, and heavy metals both in the reservoir as the sediment is disturbed and downstream after the sediment exits the reservoir.[37] Sluicing is used as a remedy to address sedimentation, but it brings with it many detrimental impacts to ecosystems within and downstream of reservoirs.[38]
Detrimental Effects of Sedimentation on Public Safety
Sedimentation brings about safety concerns, because California constructed most of its reservoirs giving little regard to sedimentation.[39] Engineers dealt with sedimentation primarily by increasing the size of a reservoir to account for anticipated sediment accumulation during the reservoir’s lifetime.[40] Engineers expected that a certain percentage of a reservoir would fill with sedimentation, thereby reducing the reservoir’s storage capacity by an acceptable amount during the reservoirs anticipated lifetime.[41] The increased reservoir capacity method of dealing with sedimentation resulted in most reservoirs in California not having lower dam outlets to release built up sediment on the reservoir floor or effective sedimentation prevention plans.[42]
California is and will continue to use many of its reservoirs well past their anticipated design lifetimes compounding the issues sedimentation causes, because as time passes and reservoirs age sedimentation becomes more difficult, expensive, and dangerous to adequately address.[43] Public safety is also effected by the changes sedimentation causes to downstream rivers, creeks, and streams because the erosion of the waterway creates a false sense of flood security for surrounding communities, encouraging the development of the traditional flood plain area.[44]
Sedimentation creates costly problems for dam operation and can lead to the eventual decommissioning of a dam if the high levels of sediment impact the dam’s structural integrity or its ability to operate the dam’s turbines or water outlets.[45] Many of California’s reservoirs will require significant maintenance in the future, and as sedimentation increases so too does the costs of that maintenance.[46] Most of California’s aging reservoirs have no immediate plan for replacement, and beyond that, California currently has no uncontroversial sites available to replace a reservoir if one were in need of emergency replacement.[47] Additionally, even if a new reservoir site were available, it would take many years to develop, litigation would be expensive and complex, and the overall cost could render it prohibitive.[48] Retrofitting and routine maintenance are necessary for a reservoir to support a specific quantity and quality of water supply in California.
Thus, sedimentation is an important issue that must be addressed before it causes significant detrimental impacts to reservoir infrastructure, ecosystems, and public safety.[49] Reservoir sedimentation is a complex problem that will not be easy to address; however, if well planned and strategized sedimentation strategies are adopted by individual reservoirs and by California as a whole the detrimental impacts of sedimentation will be more likely to be effectively and efficiently addressed.[50]
SEDIMENTATION STATISTICS IN CALIFORNIA RESERVOIRS
Big Picture Statistics
California’s reservoirs accumulated an estimated 2.1 billion cubic meters of sedimentation through 2008.[51] The accumulation of sediment has resulted a decrease of reservoir storage capacity by 4.5 percent, a significant portion of California’s total reservoir storage capacity of 47.2 billion cubic meters.[52] By the year 2200, it is projected that California’s reservoirs will contain over seven billion cubic meters of sediment equating to a loss in reservoir storage capacity of 15 percent.[53] Currently, there are more than 120 reservoirs in California have reduced storage capacities of 75 percent or more due to sedimentation, while 190 have lost 50 percent of their original capacity to sedimentation.[54] Sedimentation does not affect all reservoirs in the same way or to the same degree; however, all are affected in some form or fashion.
Reservoir Specific Statistics
Loch Lomond Reservoir located in Santa Cruz Country has a storage capacity of 8,965 acre-feet.[55] Between 1998 and 2009 an estimated 319 acre-feet of storage was lost due to sedimentation, reducing the reservoir’s water storage capacity by three percent.[56] Bethany Reservoir, located near Livermore, is part of the California Aqueduct.[57] The reservoir has been impacted so much by sedimentation that it has been forced to develop a sedimentation removal project.[58] The project’s goal is to remove sediment at the reservoir’s submerged intake structure and place it in a disposal site allowing for additional water storage capacity.[59] Englebright Lake is a reservoir on the Yuba River that impounds water from the Sierra Nevada Mountains.[60] The reservoir became operational in 1941.[61] In 2001, after the completion of multiple differencing bathymetric surveys completed at various times the estimated amount of sedimentation in Englebright Lake was 21.9 million cubic metric meters, representing 25.5 percent of the reservoir total water storage capacity.[62]
More extreme examples of sedimentation include the Rindge Dam on Malibu Creek, San Clemente Dam on the Carmel River, and Searsville Dam on the San Francisquito Creek on the San Francisco Peninsula. [63] Estimates project these reservoirs have lost 100 percent of their storage capacity due to sedimentation. [64] Although many of California’s major reservoirs were designed to minimize the impact of sedimentation by being large enough to accumulate sediment while still maintaining massive water storage capacity; sedimentation still results in significant problems for even the largest reservoirs.[65]
These are just some examples of reservoirs that would benefit from changes to the law and regulations governing reservoir sedimentation.[66] If sedimentation is not adequately addressed early in a reservoirs lifetime the potential harm, damage, and costs associated with sedimentation will increase significantly.[67] California has too many reservoirs suffering from significant sedimentation problems which is why it is essential that action be taken to effectively and efficiently address existing and future sedimentation.
IMPORTANT CONSIDERATIONS RELATED TO SEDIMENTATION IN CALIFORNIA
Removing Sedimentation from Reservoirs
Removing sediments from existing reservoirs and preventing sediments from entering reservoirs is less costly, less time consuming, and will result in more environmentally friendly outcomes than the construction of a new reservoir.[68] For example, the highly contentious reservoir proposed for on the San Joaquin River, known as Temperance Flat, would result in an increased water supply of roughly 460,000 acre-feet while at the same time it will cost billions of dollars, cause significant environmental damage, and take years of litigation to resolve.[69] On the other hand, removing sediments from existing reservoirs could increase water storage capacity by the same 460,000 acre-feet;[70] and will save millions of dollars in the process by avoiding years of litigation, evading highly contentious political battles, and causing comparatively less environmental harm than a new reservoir.[71] Thus, removing sedimentation is a more cost effective and environmentally friendly way to address sedimentation problems than constructing a new reservoir.[72]
Building/Expansion of Reservoirs
The physical expansion of a California reservoir would be expected to yield an increase of between 7 percent to 14 percent in additional reservoir capacity.[73] Conventional reservoir expansion cost is usually $1,700 to $2,700 per acre-foot of storage capacity gained.[74] Whereas, the cost of removing sedimentation is likely to be $5 to $20 a cubic yard or $8,000 to $32,000 per acre-foot.[75] Reservoir expansion costs estimates vary by reservoir. For example, expansion of Shasta Reservoir would cost $1,700 per acre-foot of water storage gained and for an additional 634,000 acre-feet of new storage capacity the estimated cost would be $1.1 billion.[76] Although reservoir expansion may be less expensive than sedimentation removal, reservoir’s cannot be expanded every time sedimentation becomes an issue and expansion does not eliminate threats to dam operation and structural integrity.
If the proposed Sites Reservoir in Colusa County is constructed, it would cost $1,800 per acre-foot of storage and supply 1.3 to 1.8 million acre-feet of new storage capacity with the estimated total cost to construct somewhere between $2.3 billion to $3.2 billion.[77] If the proposed Temperance Flat Reservoir on the upper San Joaquin River is constructed, it would cost $1,900 per acre-foot of storage gained and to supply 1.3 million acre feet of storage costing an estimated total of $2.5 billion.[78] While, expanding Los Vaqueros Reservoir would cost $2,000 per acre-foot of storage gained and would supply 60,000 acre-feet of storage for a total cost of roughly $120 million.[79] The expansion of San Luis Reservoir would cost $2,700 per acre-foot of storage gained and would cost an estimated $360 million to create enough room for an additional 130,000 acre-feet of new storage capacity.[80] Reservoir expansion is an alternative to directly addressing sedimentation; however, the costs of expansion, loss of riparian land, and the other complexities it involves are likely to make sedimentation prevention and removal techniques more appealing, efficient, and effective.[81]
EXISTING LAWS GOVERNING SEDIMENTATION IN RESERVOIRS
Statutes Governing Sedimentation
California’s reservoirs are regulated by statutes, primarily those in the Water Code.[82] The Water Code dictates that the primary agency responsible for reservoir and dam management is the California Department of Water Resources (“DWR”).[83] Additionally, the Water Code contains DWR’s grant of authority, and includes definitions for dams, reservoirs, and dam and reservoir owners.[84] DWR is responsible for the supervision of maintenance and operation of dams and reservoirs to the extent necessary to “safeguard life and property from injury.”[85] DWR has the authority to require dam and reservoir owners keep maintenance, operation, engineering, and geological investigation records, inform DWR of any unusual or surprising flooding or other circumstances affecting the dam or reservoir, and inspect dams and reservoirs to determine their safety.[86] These are important statutes but they fail to address sedimentation and the threat it poses to California’s water supply and dam operation and safety.
Regulations Governing Sedimentation
Regulations for reservoirs are in the California Code of Regulations (“Code”).[87] Under the Code, DWR is responsible for approving or denying applications for developing new reservoirs or expanding existing reservoirs, and may require specific information accompany such an application that takes into account the dam’s or reservoir’s specific circumstances.[88] The amount of information usually required by DWR for a dam or reservoir application varies based on: the proposed height of the dam; the volume of the reservoir; the possible hazards associated with both the dam and the reservoir; the hydrology in the watershed; the project and site proximity to active earthquake faults; and the dam and reservoir design complexity.[89]
DWR may also require additional information if it determines that the information is necessary for assessing the safety of the dam or reservoir.[90] Clarity is essential, thus DWR requires that all “plans, maps, specifications and other information required for an application … be … provided in sufficient clarity and detail to be readily interpreted and studied, and to permit an adequate evaluation of the safety of the proposed work.”[91] These are important regulations; however, action needs to be taken to address sedimentation now before it causes a significant loss of water storage capacity or harm to dam safety.
Recently Proposed Changes to Laws Governing Reservoir Sedimentation
Former California State Senator Fran Pavely, a Democrat from Agoura Hills, attempted to author a senate bill in the 2013-2014 legislative session to require California study reservoirs suffering from high rates of sedimentation.[92] The goal of the bill was to determine the amount of storage capacity being lost to sedimentation in the reservoirs studied and to estimate the cost of removing the sediment.[93] The bill did pass out of the Senate by a vote of 35 in favor and only one against.[94] However, it did not pass out of the Assembly because it did not get through the Appropriations Committee due to the cost associated with the bill.[95] Governor Brown’s administration commented on the bill, estimating the bill’s sedimentation studies to cost between $100,000 and $500,000 per reservoir with the cost to examine 5 percent of the California’s reservoirs to range between $6 million and $30 million.[96] Although the bill would have created a requirement to gather much of the information needed to understand the extent of sedimentation in reservoirs, it would not have established the legal requirements necessary to effectively and efficiently address sedimentation issues in California reservoirs.[97]
Recommended Changes to Laws Governing Reservoir Sedimentation
California should address sedimentation and the problems it causes through the creation of a statutory scheme developed to combat sedimentation both before and after it occurs. Properly designed a statutory scheme could effectively address reservoir sedimentation, assist with sedimentation prevention and removal projects, and allow for a more wholesome and integrated approach to reservoir management. After the enactment of a statutory scheme, DWR should pass regulations thoroughly detailing the scope of the statutory scheme, and establish standards for the funding of sedimentation related projects, such as, the collection of sedimentation data, sedimentation prevention projects, and sedimentation removal projects. The following suggested changes should be enacted by statute and emphasized by regulations to have the impact and strength necessary to effectively and efficiently address reservoir sedimentation.
Collect Specific Information and Data
A statutory scheme should include a requirement that specific information and data must be gathered related to sedimentation, because most reservoirs have not been studied or surveyed to estimate the amount or rate of sedimentation that is accumulating on reservoir floors.[98] Managers and operators of reservoirs have very little reliable data related to sedimentation, despite the data’s usefulness in determining a reservoir’s water capacity, general safety, and structural integrity.[99] Reservoir and dam owners, managers, and operators would benefit from the completion of specific studies to identify reservoirs that will likely fill with enough sediment to detrimentally impact reservoir’s storage capacity or physical integrity and help develop effective sedimentation management programs.[100]
To enhance reservoir sedimentation prevention and removal the statutory scheme should specify all reservoirs provide DWR with sedimentation data as part of the information required. DWR should then be required to use the information to make decisions related to reservoir sedimentation management at a state wide and individual reservoir basis, keeping its priority on preventing and removing potential threats to the dam or reservoir. The information and data gathered should include, but not be limited to: information related to the overall amount of accumulated sediment; the geographic spread of the sedimentation; the toxicity of the sedimentation; current and future projections of the rate of sedimentation; and major upstream sources of the sediment, e.g. upstream erosion or fire debris. Accurate and reliable information and data related to sedimentation is crucial to an effective and efficient statutory scheme and the development of sedimentation management strategies at a statewide and individual reservoir level.
Mandate the Development of Sedimentation Models
Statutorily requiring predictive sedimentation models that meet specified scientific standards would assist sedimentation projection accuracy and allow for more informed responses to combat sedimentation.[101] Existing models used to determine and predict sedimentation are primarily process-based models.[102] These models use small spatial and temporal scales when making determinations regarding sedimentation in reservoirs.[103] However, small spatial and temporal scales for models is not the best way to calculate sedimentation.[104]
Sedimentation models meeting specified standards should be statutorily required for reservoirs based on the severity of the impact sedimentation is having on the reservoir and the importance of the reservoir to California’s water supply and water infrastructure, because models will likely result in improved planning for sedimentation strategies at a statewide and individual reservoir basis. A new method or methods to gather sedimentation data for reservoirs should be created to provide more accurate information based on real-time conditions.[105] Author’s J. Toby Minear and G. Matt Kondolf provide recommended methods for modeling sedimentation data which at its basic premise consists of “(1) a determination of sediment yield by geomorphic region from measured reservoir sedimentation rates and (2) the application of this sediment yield rate to unmeasured reservoirs in each region.”[106] Sedimentation modeling is complex and requires the development of mathematical formulas, however it can be successfully accomplished. Whether the model presented here, or other(s) should be adopted is beyond the scope of this analysis; however, if sedimentation is going to be effectively and efficiently addressed accurate and up to date models need to be created.[107]
Best Available Technology (BAT) Standard
Statutorily requiring the use of a best available technology (BAT) standard to conduct reservoir analysis of sedimentation should also be required. A BAT standard will help ensure the sedimentation information gathered is reliable and accurate.[108] The federal Clean Water Act (“CWA”) currently has in place a BAT standard that can be used as a reference in developing a BAT standard for sedimentation.[109] The reason a BAT standard should be created is because BAT standards allows for the use of the best available technology that is economically achievable, taking into account the cost of achieving the BAT, the facilities unique characteristics to which the BAT will apply, other environmental impacts caused by achieving the BAT including energy impacts, and other factors deemed appropriated by the regulating agency.[110]
A BAT standard is not the only standard used in environmental law that could be adopted to address sedimentation A standard could be developed that is more similar to the Clean Air Act’s (“CAA”) reasonably available control technology (“RACT”) standard or its lowest achievable emissions rate (“LAER”) standard.[111] However, these standards do not provide the same benefits a BAT standard provides because a RACT standard does not require the best technology taking into consideration the costs and a LAER requires the best technology available no matter the cost.[112]
Creating a BAT standard for reservoir sedimentation analysis would require sedimentation studies use the best most effective and reliable technology.[113] However, a BAT standard would allow for the consideration of the cost of the potential technologies, the different energy consumptions rates of those technologies, and the various environmental impacts of the technologies.[114] Additionally, a BAT standard will allow for a case-by-case analysis of each reservoir, permitting reservoir studies be completed using the best technology for that specific reservoir.[115] Lastly, a BAT standard will encourage the development of new and more accurate scientific methods and devices for understanding and gauging sedimentation patterns in California reservoirs.[116] Thus, statutorily requiring a BAT standard would be beneficial for each reservoir studied and for the state of California as a whole.[117]
Timeframes for the Assessment of Sedimentation in Reservoirs
Statutorily requiring specific timeframes for assessing reservoir sedimentation rates is also essential to a new strategy to address the sedimentation of California’s reservoir. Studying the sedimentation rate of every reservoir in California is not a realistic mandate.[118] However, an analysis of every reservoir supplying above a specified amount of water or certain reservoirs designed to trap contaminated sediments is a reasonable requirement if enough time is allotted for the completion of the sedimentation analyses and public funds were made available for the studies to be conducted.
Require the Categorization of Reservoirs Based on Amount of Sedimentation
Another potential legal requirement could be to require DWR to categorize reservoirs as high priority, medium priority, and low priority, and require action be taken to address sedimentation based on the priority level assigned to the reservoir. The factors considered in the determination of a reservoir’s priority level should include the reservoir’s storage capacity, current sedimentation level, structural integrity, importance to California’s water supply infrastructure, and the anticipated rate of future sedimentation. The categorization of the reservoirs will allow for sedimentation in high and medium priority reservoirs be addressed more quickly than low priority reservoirs and will provide organization by putting emphasis on reservoirs with more severe sedimentation concerns.
Furthermore, statutorily requiring reservoirs engage in supplemental sedimentation analyses based on the reservoir’s priority level would allow for the development of the best possible sedimentation management plans for individual reservoirs and the state as a whole. For example, reservoirs could be designated high priority requiring sedimentation analyses be completed every five years, medium priority requiring analysis every 10 years, and low priority requiring analysis every 20 years. Requiring timeframes and priority levels for reservoir sedimentation analyses, by statute or regulation, would provide the additional information to DWR that is needed to ensure effective and efficient sedimentation management plans at a statewide and individual reservoir level.
Funding Program to Address Sedimentation
Programs and projects to address sedimentation, such as information and data gathering, prevention, and removal projects, will require significant financial investment. Public funding should be made available for entities to engage in various types of approved sedimentation programs and projects, because without public funding sedimentation will not be successfully addressed. Creating a public funding scheme through statutes and regulations to address sedimentation could be accomplished through in several ways, including but not limited to: the state budget process; a proposition approved by the voters; or a legislative enactment. No matter the method taken, the initial budget should be no smaller than the minimum dollar amount that is estimated to be required to provide assurance that the funding program is implemented properly and funds a minimum number of projects and project types before being assessed for success and the potential for additional funding.
Sedimentation prevention and removal funding will create encourage and place emphasis on sedimentation prevention and removal projects, because it will allow dam and reservoir owners and operators to address sedimentation problems without being forced to bear all the costs. Funding made available for sedimentation programs and projects should be dispersed based on criteria developed statutorily or by DWR because DWR should have the authority to grant funds for sedimentation programs and projects. DWR should be given this authority because it currently has many types of programs for projects it funds, including programs for environmental restoration, groundwater, and water supply and management.[119] To ensure funding granted by DWR is being used to effectively address reservoir sedimentation, DWR should be permitted the authority to create standards for the various types of sedimentation projects, including but not limited to: sedimentation information and data collection; sedimentation prevention; and sedimentation removal projects.
Creation of a fund to support and encourage sedimentation prevention and removal projects will not be easily accomplished or implemented. The fund will take time and money to develop and implement, but it will produce benefits that include improvements to water quality and water supply capacity as well as infrastructure and safety. [120] The positive impact an effective reservoir sedimentation strategy could have on water supply capacity and infrastructure includes, but is not limited to: increases to reservoir water supply capacity; decreases in the accumulation of toxic contaminants on the reservoir floor; and healthier in-reservoir and downstream ecosystems.[121]
Require Action to Reduce Sedimentation
Mandating information and data gathering, sedimentation modeling, a best available technology (BAT) standard, sedimentation categorization and prioritization, and providing funding alone is not enough. A requirement that action be taken by reservoir owners to engage in the sedimentation program managed by DWR should be put in place to have a chance at adequately addressing sedimentation. The type of action taken to remove or prevent sedimentation are likely to vary based on the unique characteristics of the reservoir, including, but not limited to: the degree of sedimentation in the reservoir; the rate of future reservoir sedimentation; the economic costs of not dealing and dealing with sedimentation; the public safety risks of sedimentation; and the potential environmental harms. Sluicing, removal, and other techniques should all be explored as potential actions that would be projects that qualify for government funding. The type of sediment, the structure of the dam, the location of dam outlets, the location of the sedimentation in the reservoir, and the size and importance of the reservoir for California’s water supply are also important factors that should be considered.
California should require these and other actions that the legislature deems appropriate when creating the statutory scheme for reservoir sedimentation management. A statutory scheme is the best way to address sedimentation; however, key to that scheme are the recommendations for changes to current laws governing sedimentation. Gathering information and data, generating models with scientific standards, enacting a BACT, drafting timeframes for reservoir sedimentation assessments including prioritizing reservoirs with higher levels of sedimentation related problems, the categorization of reservoirs based on the severity of the impact sedimentation is having or is likely to have on the reservoir, a funding program with sufficient capital, and the requirement that action be taken to address sedimentation in reservoirs that meet a specific category are all necessary to effectively deal with sedimentation.
CONCLUSION
Sedimentation is a threat to California because it detrimentally impacts water supply, water quality, public safety, and the environment. Reservoir sedimentation is an ongoing issue that California will face as its reservoirs continue to age and pass their anticipated lifetimes. Therefore, creating a statutory framework that requires the use of specific tools to identify reservoirs at higher risk of filling with sediment in the future, standards for the technology used to measure and gauge sedimentation, and a priority ranking system for reservoir’s based on their level of sedimentation will assist in the anticipation and development of countermeasures to be implemented to prevent sedimentation in current and future reservoirs.
Sedimentation is a threat California must take seriously because water is vital to California’s success. Water supply has always been a multifaceted issue in California and recent drought conditions have only added to the historic complexities. Amid weather fluctuations and global climate change it has become even more important than it previously was to effectively and efficiently manage water resources. California’s historical weather patterns are changing, and models used to predict weather patterns are becoming outdated and inaccurate. Water availability, and therefore water storage, is one of the most important issues facing California because of its unique climate, abundance of agriculture, accelerated population growth, and aging water infrastructure. Thus, California cannot afford to ignore the dangerous threats that sedimentation of reservoirs poses, and action should be taken as recommended. Sedimentation should be addressed now because “we don’t inherit the earth from our ancestors, we borrow it from our children,” and future generations should not be left to deal with problems that this generation can work to address today.[122]
* Ryan John Mahoney, JD ‘17, LLM ‘17, McGeorge School of Law, is staff counsel with the California Office of Environmental Health Hazard Assessment. This thesis, and the opinions expressed herein, are the author’s and do not necessarily represent the views of the State of California, the California Environmental Protection Agency, or the Office of Environmental Health Hazard Assessment.
[1] Aubrey Mescher, Reservoir Sedimentation and Water Supply Reliability, Aspen Environmental Group, 3, 4, 5, (May 3, 2013) http://www.aspeneg.com/wp-content/uploads/2013/05/Reservoir-Sedimentation-Article-AM-REV-050313-4.pdf (last visited April 4, 2017); see Cal. Dept. of Water Res., A Resource Management Strategy of the California Water Plan 1, 2, 3 (Jul. 29, 2016), available at http://www.water.ca.gov/waterplan/docs/rms/2016/25_Sediment_Mgt_July2016.pdf (last visited Jan. 28, 2018) [hereinafter Resource Management Strategy]; see U.S. Dept. of the Interior Bureau of Reclamation, Reservoir Sedimentation A Technical Guideline for Bureau of Reclamation 1-2 (Oct. 1982), available at http://www.water.ca.gov/waterplan/docs/rms/2016/25_Sediment_Mgt_July2016.pdf (last visited Jan. 28, 2018) [hereinafter Sedimentation A Technical Guideline].
[2] Mescher, supra note 1, at 3, 4, 5; see Resource Management Strategy, supra note 1, at 1, 2, 3; see Sedimentation A Technical Guideline, supra note 1, at 1-2.
[3] See California Water 101, Water Education Foundation, http://www.watereducation.org/photo-gallery/california-water-101 (last visited Jan. 28, 2018); Sedimentation A Technical Guideline, supra note 1, at 1, 2.
[4] Mescher, supra note 1, at 3, 4, 5; see Resource Management Strategy, supra note 1, at 1, 2, 3; see Sedimentation A Technical Guideline, supra note 1, at 1-2.
[5] Aubrey Mescher, supra note 1, at 3, 4, 5; see Resource Management Strategy, supra note 1, at 1, 2, 3; see Sedimentation A Technical Guideline, supra note 1, at 1, 2, 3.
[6] Ryan Richards, It’s not just Oroville: Most dams across the country have passed their designated lifespan, Think Progress (Feb. 15, 2017), https://thinkprogress.org/oroville-aging-dams-across-the-country-94386c1982ce/ (last visited Jan. 28, 2018); Erin Mellon, Undated Information Released on California Dams, Cal. Dept. of Water Res. 1 (Sept. 1, 2017), available at http://www.water.ca.gov/news/newsreleases/2017/090117news.pdf (last visited Jan. 28, 2018).
[7] Jonas Minton, The Old and the New: Evaluating Existing and Proposed Dams in California, 2 Golden Gate U. Envtl. L.J. 96, 103 (2008).
[8] Minton, supra note 7, at 96, 103.
[9] Mescher, supra note 1, at 1.
[10] Mescher, supra note 1, at 1.
[11] See Minton, supra note 7, at 96, 103; Mescher, supra note 1, at 1.
[12] Mescher, supra note 1, at 1.
[13] M. Rhead Enion, Rethinking National Wildlife Federation v. Gorsuch: The Case for Npdes Regulation of Dam Discharge, 38 Ecology L.Q. 797, 805 (2011).
[14] M. Rhead Enion, supra note 13, at 797, 805; Minton, supra note 7, at 96, 103.
[15] M. Rhead Enion, supra note 13, at 797, 805; Minton, supra note 7, at 96, 103.
[16] Justin Minear, Reservoir Sedimentation Related to Wildfire in the Sierra Nevada Mountains of California, U.S. Geological Serv., https://ca.water.usgs.gov/projects/2014-15.html (last visited April 4, 2017).
[17] Mescher, supra note 1, at 1.
[18] Mescher, supra note 1, at 1.
[19] Mescher, supra note 1, at 8, 9.
[20] Alison M. Dornsife, From A Nonpollutant into A Pollutant: Revising EPA’s Interpretation of the Phrase “Discharge of Any Pollutant” in the Context of Npdes Permits, 35 Envtl. L. 175, 177 (2005).
[21] See Mescher, supra note 1, at 1.
[22] See Karlie Shea Clemons, Comment, Hydroelectric Dams: Transboundary Environmental Effects and International Law, 36 Fla. St. U. L. Rev. 487, 496 (2009) (“…extreme cases, sediment buildup can put additional pressure on the dam itself, which can actually weaken the dam”).
[23] Mescher, supra note 1, at 3.
[24] See Mescher, supra note 1, at 3; see Raju Shresthra and Dorothee Spuhler, Sedimentation, Sustainable Sanitation and Water Management, https://www.sswm.info/content/sedimentation (last visited Feb. 5, 2018).
[25] Matthew William George, Reservoir Sedimentation: The Economics of Sustainability, Brigham Young University 1 (Jun. 1, 2016) available at https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=6954&context=etd (last visited Jan. 30, 2018).
[26] George, supra note 25, at 1, 3; Jay Lund, Should California Expand Reservoir Capacity by Removing Sediment?, Univ. of Cal., Davis (June 9, 2016), https://californiawaterblog.com/2014/06/09/should-california-expand-reservoir-capacity-by-removing-sediment/ (last visited March 3, 2017).
[27] See James E. Evans, Contaminated Sediment and Dam Removals: Problem or Opportunity, Earth & Space Science News (Oct. 8, 2015) available at https://eos.org/features/contaminated-sediment-and-dam-removals-problem-or-opportunity-2 (last visited Jan. 30, 2018).
[28] See Evans, supra note 27; Catherine C. Engberg, The Dam Owner’s Guide to Retirement Planning: Assessing Owner Liability for Downstream Sediment Flow from Obsolete Dams, 21 Stan. Envtl. L.J. 177, 180 (2002).
[29] See Evans, supra note 27; Engberg, supra note 28, at 180.
[30] See Evans, supra note 27.
[31] See Mescher, supra note 1, at 3.
[32] Engberg, supra note 28, at 183, 184-185; J. Toby Minear and G. Matt Kondolf, Estimating Reservoir Sedimentation Rates at Large Spatial and Temporal Scales: A Case Study of California, 45 Water Resources Research, at 1, 2, (Dec. 25, 2009) available at http://onlinelibrary.wiley.com/doi/10.1029/2007WR006703/epdf (last visited Jan 27, 2018)[hereinafter Estimating Reservoir Sedimentation].
[33] Engberg, supra note 28, at 184-185.
[34] Mescher, supra note 1, at 3.
[35] Lund, supra, note 26.
[36] Lund, supra, note 26; see Eduardo J, Martin, Michael Doering, and Christopher T. Robinson, Ecological Effects of Sediment Bypass Tunnels, International Workshop on Sediment Bypass Tunnels, at 1, 2, Apr. 2015, available at http://www.eqcharta.ch/index_htm_files/SBT%20Martin.pdf (last visited Jan. 30, 2018)[hereinafter Ecological Effects of Sediment Bypass Tunnels].
[37] Lund, supra, note 26; Dornsife, supra note 20, at 177.
[38] See Ecological Effects of Sediment Bypass Tunnels, supra note 36, at 1, 2.
[39] Engberg, supra note 28, at 178; see Minton, supra note 7, at 2.
[40] See Mescher, supra note 1, at 1.
[41] See Mescher, supra note 1, at 1.
[42] See Engberg, supra note 28, at 178; Estimating Reservoir Sedimentation, supra note 32, at 1.
[43] Estimating Reservoir Sedimentation, supra note 32, at 1, 3.
[44] Engberg, supra note 28, at 184-185.
[45] Estimating Reservoir Sedimentation, supra note 32, at 1, 2.
[46] Id.
[47] Kent Collins, Sean Kimbrel, Tim Randle, Formulating Guidelines for Reservoir Sustainability, 2, available at https://acwi.gov/sos/pubs/3rdJFIC/Contents/8C-Kimbrel.pdf (last visited March 4, 2017).
[48] Id.
[49] Mescher, supra note 1, at 3; See Estimating Reservoir Sedimentation, supra note 32, at 1.
[50] Mescher, supra note 1, at 5, 6; See Estimating Reservoir Sedimentation, supra note 32, at 1.
[51] Estimating Reservoir Sedimentation, supra note 32, at 1, 6.
[52] Id.
[53] Id. at 1, 6, 7.
[54] Glen Martin, No Joy in Mudville: Amid Drought, California’s Reservoirs are Clogged with Gunk, California Magazine (June 5, 2014) available at https://alumni.berkeley.edu/california-magazine/just-in/2014-06-09/no-joy-mudville-amid-drought-californias-reservoirs-are (last visited March 3, 2017).
[55] Kelly R. McPherson, Lawrence A. Freeman, and Lorraine E. Flint, Analysis of Methods to Determine Storage Capacity of, and Sedimentation in, Loch Lomond Reservoir, Santa Cruz County, California, U.S. Geological Serv. 1 (2009), available at https://pubs.usgs.gov/sir/2011/5141/pdf/sir20115141.pdf (last visited March 3, 2017)[hereinafter Analysis of Methods].
[56] Id.
[57] Cal. Dept. of Water Res., Bethany Reservoir Sedimentation Removal, http://wwwoandm.water.ca.gov/bethany_res_sediment.cfm (last visited April 4, 2017).
[58] Id.
[59] Id.
[60] Snyder, N. P., D. M. Rubin, C. N. Alpers, J. R. Childs, J. A. Curtis, L. E. Flint, and S. A. Wright (2004), Estimating Accumulation Rates and Physical Properties of Sediment Behind a Dam: Englebright Lake, Yuba River, northern California, Water Resources Research,, 4 (October 29, 2004) available at http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1498&context=usgsstaffpub (last visited March 3, 2017).
[61] Id.
[62] Id.
[63] Martin, supra note 54.
[64] Martin, supra note 54.
[65] See Estimating Reservoir Sedimentation, supra note 32, at 1, 2; 33 U.S.C.A. § 1311(b)(2)(A) (West, Westlaw through 2017); see Jay Lund, Expanding Water Storage Capacity in California, California Water Blog (Feb. 22, 2012) https://californiawaterblog.com/2012/02/22/expanding-water-storage-capacity-in-california/ (last visited Feb. 5, 2018).
[66] Mescher, supra note 1, at 1.
[67] See Estimating Reservoir Sedimentation, supra note 32, at 1, 2; 33 U.S.C.A. § 1311(b)(2)(A) (West, Westlaw through 2017).
[68] See Lund, supra note 65.
[69] Martin, supra note 54.
[70] Martin, supra note 54.
[71] Martin, supra note 54.
[72] See Lund, supra, note 26.
[73] Id.
[74] Id.
[75] Id.
[76] Id.
[77] Id.
[78] Id.
[79] Id.
[80] Id.
[81] See Id.
[82] Cal. Wat. Code, § 6000 et seq. (Westlaw, Westlaw through 2017).
[83] Id. at §§ 6075, 6076, 6078.
[84] Id. at §§ 6002, 6004.5, 6005.
[85] Id. at § 6100.
[86] Id. at § 6101.
[87] Cal. Code Regs., tit. 23, § 301 et seq. (Westlaw, Westlaw through 2017).
[88] Id. at § 310(a)-(b).
[89] Id. at § 310(c).
[90] Id. at § 310(e).
[91] Id. at § 310(d).
[92] Sen. Bill 1259, Bill History, 2013-2014 Reg. Sess. (Cal. 2014) available at http://leginfo.legislature.ca.gov/faces/billHistoryClient.xhtml?bill_id=201320140SB1259 (last visited April 5, 2016)[hereinafter Bill History].
[93] Id.
[94] Id., George Skelton, California’s Reservoirs are Filled with Gunk, and it’s Crowding Out Room to Store Water, Los Angeles Times, (March 6, 2017) http://www.latimes.com/politics/la-pol-sac-skelton-silt-california-dams-20170306-story.html (last visited March 3, 2017).
[95] Bill Analysis, supra note 92.
[96] Skelton, supra note 94; Tina Leahy, Assembly Committee on Water, Parks, and Wildlife Committee Analysis SB 1259, Assembly Committee on Water, Parks, and Wildlife, 1 (May27, 2014) available at http://leginfo.legislature.ca.gov/faces/billAnalysisClient.xhtml?bill_id=201320140SB1259 (last visited April 5, 2017).
[97] See Skelton, supra note 94; Leahy, supra note 96, at 1.
[98] Estimating Reservoir Sedimentation, supra note 32, at 7.
[99] See Id. (“[g]iven that most reservoirs have not been surveyed for sedimentation, managers could benefit from a tool with which to identify at a regional level those reservoirs at higher risk of filling in the near future so that problems can be anticipated and countermeasures can be explored and implemented such as installation of upstream sediment traps, sediment pass-through, flushing, or mechanical removal”).
[100] Id.
[101] Id. at 1, 2, 7.
[102] Id. at 1.
[103] Id.
[104] Id.
[105] Id. at 1, 7.
[106] Id. at 3.
[107] Id. at 1, 7.
[108] U.S. Envtl. Prot. Agency, Learn About Effluent Guidelines, https://www.epa.gov/eg/learn-about-effluent-guidelines (last visited Jan. 30, 2018).
[109] 33 U.S.C.A. § 1311(b) (West, Westlaw through 2017).
[110] 42 U.S.C.A. §§ 7479(3) (West, Westlaw through 2017).
[111] Id. at § 7503(a)(2); 40 C.F.R. §§ 51.100, 51.165(a)(1)(xiii) (West, Westlaw through 2017).
[112] 42 U.S.C.A. §§ 7475(a)(4), 7479 (West, Westlaw through 2017); 33 U.S.C.A. § 1311(b) (West, Westlaw through 2017).
[113] Id. at §§ 7479(3) (West, Westlaw through 2017).
[114] Patricia Ross McCubbins, The Risk in Technology-Based Standards, at 4, 5, (2005), Duke Univ., available at https://scholarship.law.duke.edu/cgi/viewcontent.cgi?referer=https://www.google.com/&httpsredir=1&article=1096&context=delpf (last visited Jan. 30, 2018); 33 U.S.C.A. § 1311(b)(2)(A) (West, Westlaw through 2017).
[115] 33 U.S.C.A. § 1311(b)(2)(A) (West, Westlaw through 2017). 42 U.S.C.A. § 7479 (West, Westlaw through 2017).
[116] See Estimating Reservoir Sedimentation, supra note 32, at 1, 2; 33 U.S.C.A. § 1311(b)(2)(A) (West, Westlaw through 2017).
[117] See 33 U.S.C.A. § 1311(b)(2)(A) (West, Westlaw through 2017); See Estimating Reservoir Sedimentation, supra note 32, at 1, 2; see McCubbins, supra note 114, at 4, 5, (2005).
[118] See Skelton, supra note 94; see Leahy, supra note 96, at 1.
[119] Cal. Dept. of Water Res., Financial Assistance, http://www.water.ca.gov/funding/ (last visited Jan. 30, 2018).
[120] Nevada Irrigation District, Cal. Dept. of Fish & Game, and CALFED Ecosystem Restoration Program, Combie Reservoir Sediment & Mercury Removal Project, Cal. Dept. of Fish and Wildlife 5, 6 (Mar. 1, 2011), available at file:///C:/Users/ryj70/Downloads/2010-019.pdf (last visited Jan. 16, 2018); Skelton, supra note 94; Leahy, supra note 96, at 1.
[121] Id.
[122] Kevin E Trenberth, Are We Good Stewards of the Planet Earth, Graduation Address to Bridge School, Boulder (May 30, 2008) available at http://www.cgd.ucar.edu/cas/Trenberth/website-archive/gradSp2-moved.pdf (last visited Jan. 28, 2018).
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