CalAm Use of Carmel River Groundwater Basin

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A watershed-related issue examined by the ENVS 560/L Watershed Systems class at CSUMB.


California American Water (CalAm) is the private company that provides the Monterey Peninsula their drinking water. The Carmel Watershed and the Seaside Groundwater Basin are the primary sources of fresh water for CalAm. The California American Water Company (Cal-Am) utilizes 21 wells along the Carmel River Watershed to divert water from the Carmel river and alluvial aquifer. CalAm has legal water rights to 3,376 acre feet from the Carmel River, but has been overpumping for years. [1] The State Water Resources Control Board (SWRCB) issued a cease and desist order on CalAm which has not been headed to. With rising rates for drinking water, controversy and oppostion to CalAm and their control over Monterey's water has increased. A push for a public buyout has been pursued to remove CalAm from controlling the water in Monterey. CalAm proposed and began planning for alternative water supply sources including Pure Water Monterey and a desalination plant using ocean water to lessen the reliance on the Carmel River. [2]

Despite increased conservation efforts, demand for water in the Monterey Peninsula exceeds supply and alternative water sources are still in the planning stages. Cal-Am continues to illegally divert water from the Carmel River in order to meet the water demands of the Monterey Peninsula. In November 2015, Cal-Am submitted a proposal to extend the December 2016 deadline until 2020 with modest diversion reductions as they continue to work on the Monterey Peninsula Water Supply Project. [3] [4]


  • The Carmel Watershed is 255 square miles located in Monterey County, CA. The region is bounded by the Santa Lucia mountain range to the southwest and the Sierra de Salinas mountains to the Northeast.
Carmel BaseMap +Elev.png

Resources at stake


The primary resource of concern in this watershed-related issue is the water captured by the Carmel Watershed. The surface water supplies were originally thought to be a separate resource from the groundwater, however in 1995 the SWRCB ruled that the groundwater wells were subject to SWRCB jurisdiction [5]. California's Groundwater Bulletin 118 estimated the groundwater storage capacity of the Carmel Valley basin to be between 36,000 and 60,000 acre-feet [6].

The Seaside groundwater basin is the only other water source Cal-Am uses to supply the Monterey Peninsula[5]. This basin has a safe yield of 3,000 AF/year, but is being drafted at a rate of 5,600 AF/year[7].

An adjudication decision in 2008 limited the amount of water that can be taken out of the Carmel River to 11,285 AF/year and out of the Seaside Basin to 3,504 AF/year[8].

Steelhead Trout and Red-legged Frogs

Many are concerned about overdrafting the Carmel River because it is home to a Steelhead population and Red-legged frogs. Steelhead and Red-legged frogs in the South-Central California region are a federally threatened species [9] [10] and are protected under the federal Endangered Species Act. Order 95-10 found Cal-Am diversions to be the largest single adverse effect on fish, wildlife, and riparian habitat in the Carmel River. [11] The lower 6.5 miles of the Carmel River are dry 5-6 months out of every year primarily due to Cal-Am diversions. [12] In 2005, the Carmel River was listed as critical habitat for Steelhead. [13]

Kevan Urquhart, a Senior Fisheries Biologist for the Monterey Peninsula Water Management District, testified before the State Water Resources Control Board to determine if there should be a Cease & Desist Order against CalAm because of their diversions from the Carmel River under Order 95-10. Urquhart testified:

• The first two CalAm diversion cuts will not significantly improve Steelhead or Red-legged frog habitat. The elimination of CalAm’s illegal diversions is necessary for a complete Steelhead recovery. The elimination of diversions is not an emergency measure because the proposed first two cuts in diversions will not affect the wetness of the river year round.

• Cutbacks in diversions during the summer/fall low flow season would be most beneficial

• If the 4 proposed cutbacks were implemented, there might be flows to the lagoon for a month to a month and a half longer during critically dry years. In normal years, flows may be prolonged two and half weeks to a month later. During wetter years, there may be flows to the lagoon a month to a month and two thirds longer.

• Dredging the Los Padres Reservoir and expanding the Aquifer Storage and Recovery in the Seaside basin would be more effective mitigation strategies to recover the aquatic habitat.[14]

Agriculture and Tourism

There are many vineyards that depend on water from the Carmel Watershed. Some of the winemakers growing grapes in the Carmel watershed include: Georis, Parsonage, Bernardus, Boete, Chateau Julien, Chataeu Sinnet, Cima Collina, Figge Cellars (Pelio Vineyard), Galante, Hellar Estate, Joullian and Talbott Vineyards [15].

Several golf courses are maintained within and nearby the Carmel watershed. The golf industry brings many tourists to the Monterey area [16].

Inherent Value

The Carmel River is also a valued part of the community and is a social resource. The river's aesthetic and source of community leisure and relaxation is a resource that cannot be easily quantified. "The Carmel is a lovely little river. It isn't very long but in its course it has everything a river should have" John Steinbeck, Cannery Row, 1945


Laws, policies, & regulations

Under the California permit system, once a permittee has completed construction of a diversion structure and applied the water to beneficial use, the State Water Resources Control Board (SWRCB) investigates to confirm completion and compliance. The SWRCB will issue a license confirming the amount of water found to have been perfected by reasonable beneficial use subject to the terms and conditions included in the permit and required by statute and California case law. [17]

Between 1987 and 1991 the SWRBC received formal complaints from four stakeholder organizations within the Carmel Valley: the Carmel River Steelhead Association, the Sierra Club, the Residents Water Committee, and the California Department of Parks and Recreation. Complaints alleged that pumping of the Carmel River Aquifer by Cal-Am:

  • Caused observable recession of the Carmel River riparian zone
  • Was Destroying habitat for the then threatened post 1998 endangered Steelhead
  • Violated the public trust doctrine stating that the harvesting of a public resource (Carmel River water) must not interfere with the ability of the public to utilize that resource [11].

Order 95-10

The SWRCB issued Order 95-10 [11] stating that Cal-Am had a legal right to 3,376 acre-feet per year (afy) of water from the Carmel river:

  • Pre-1914 appropriative right: 1,137 afy
  • Riparian rights: 60 afy
  • Appropriative right to divert water to the Los Padres Reservoir: 3,030 afy (actually 2,179 afy due to reduced reservoir capacity) [11]

Order 95-10 estimated that Cal-Am diverted 14,106 afy from the Carmel Watershed, 10,730 afy over their legal right (69% of water supplied to the Monterey Peninsula). [18] In 1995, Cal-Am was restricted to an annual diversion of 11,285 afy from the Carmel Watershed until an alternate water supply could be developed. Cal-Am was required to implement an urban water conservation plan to conserve 15% in 1996 and 20% every year after. Cal-Am failed to conserve 20% in 1997 and was fined $168,000. The fines were suspended when Cal-Am proposed water conservation measures in Pebble Beach that would reduce water consumption by 400-500 afy.

In 2007 the SWRCB issued Permit 20808A authorizing an additional diversion of 2,426 afy water to the Seaside Groundwater Basin. [18]

In 1995 the SWRCB upheld the allegations of the Carmel River stakeholder groups, determining that Cal-Am had no legal right to 10,730 acre-feet of the 14,000 drafted annually and passed Order WR 95-10 [11]. This Cease and Desist order included a mitigation plan requiring that Cal-Am reduce the amount pumped from the Carmel River via a series of options.

These options included:

  • Appropriating/purchasing legal rights to the water in overdraft
  • Greater reliance on the nearby Seaside Aquifer
  • Building of a new dam and/or exploration of alternative and renewable sources of fresh water such as desalination and waste water treatment.

Since Cal-Am actions were found to be "taking" a threatened species (Steelhead), Order WR95-10 exposed Cal-Am to prosecution by the federal government under the Endangered Species Act [19]. This additional legal action resulted in a settlement agreement between Cal-Am and the National Marine Fisheries Service in which Cal-Am agreed to implement measures to "reduce the impact of its operations in the Carmel River on Steelhead and their habitat" [20].


MPWMD water production graph.png
  • Seventy five percent of the Monterey Peninsula's water supply is pumped from the Carmel River alluvial aquifer [21]. If there is not equivalent recharge to replenish the pumped water, the water table will decrease. Irrigation along the channel of the Carmel river mitigates vegetation mortality and bank erosion caused by a depressed water table [22].
  • Two threatened species, red-legged frogs (Rana aurora) and steelhead (Oncorhynchus mykiss), depend on the Carmel River for habitat.


Watershed assessments and action plans have been conducted for the Carmel River watershed. A comprehensive understanding of the watershed as a whole, surface water, groundwater and water use, enables CalAm use of the Carmel River groundwater basin to be contextualized and studied.


The Monterey Peninsula Water Management District (MPWMD) is responsible for the monitoring of surface and groundwater production on the Carmel river watershed. They have a variety of tools at their disposal:

  • Monitoring Wells
    • Currently, MPWMD possesses 27 groundwater wells that are primarily used for monthly measurements on water quality and aquifer height [23].
    • The District also has access to 1,000 registered and metered wells inside the Carmel watershed [23].
    • Groundwater well sites are also used to test for potential seawater intrusion via monthly experiments observing nitrate, chloride, sodium and 12 other constituents concentrations [23].
  • Surface Discharge Gages
    • MPWMD uses 2 continutes recording stream flow gages (owned operated by USGS)
      • Via Mallorca road near Carmel by the sea [24].
      • Robles del Rio road just above Carmel Valley [25].
  • Computer Simulation Models
    • Data combined from wells and surface flows can be used to create predictor models of hydrological flow in a watershed.
    • Numerous modeling software is available, examples can be found below:
      • HEC-HMS (US Army Corps of Engineers) [26] [27]
      • Schulumberger Water Services Westbay System [28]
        • Schulumberger is a globally recognized private cooperation innovator of technologies and solutions engineered to support groundwater professionals.
      • Tarsier (CSUMB Watershed Institute package) [29].
        • Case study using Tarsier: Watson and Casagrande (2004) [30].
  • Environmental Tracers

Future research

Future research in the Carmel watershed could study capacity issues in the Carmel aquifer. More information is needed on the amount of water that ca be extracted without the risk of land subsidence, loss in aquifer storage capacity, or salt water intrusion. A granite sill protects the Carmel aquifer from significant saltwater intrusion (unlike in the Salinas Valley[33] ) but questions remain as to how much water can be extracted from the aquifer before salt water intrusion occurs. These issues require attention to avoid irreversible problems that will limit available fresh water supplies to the Monterey Peninsula.

Master's candidates in the Coastal and Watershed and Environmental Policy program at California State University of Monterey Bay could model the groundwater aquifer with visualizations for policy purposes. With unlimited funding, one could set up real time measuring wells throughout the Carmel watershed to develop a 3D model of the entire aquifer. Graduate students could investigate the minimal water level required to avoid land subsidence and salt water intrusion into the Carmel aquifer. Tracers could be used in combination with models to look at groundwater recharge.



  1. Carmel-By-The-Sea
  2. [1]
  3. California American Water petitions to extend Carmel River cutback order, Business Wire
  4. Cal-Am request to change Order WR 2009-0060, SWRCB
  5. 5.0 5.1 Monterey's Coastal Water Project
  6. California's Groundwater Bulletin 118
  7. Seaside Groundwater Basin Report
  8. Monterey Court Adjudication Decision
  9. South-Central California Steelhead Status
  10. Red-Legged Frog
  11. 11.0 11.1 11.2 11.3 11.4 Order WR 95-10
  12. Cite error: Invalid <ref> tag; no text was provided for refs named CDO2009
  13. 70 Fed. Reg. 52488
  14. Urquhart testimony
  15. Carmel Valley Chamber of Commerce
  16. See Monterey
  17. California Water Code
  18. 18.0 18.1 EIR Water Demand and Supply
  19. Endangered Species Act
  20. Cal-Am NMFS Settlement Agreement
  21. Carmel River Watershed: Water Supply Perspective
  22. Physical and Hydrologic Assessment of the Carmel River Watershed California
  23. 23.0 23.1 23.2 Carmel River Mitigation Program
  24. Carmel River gage near Carmel
  25. Carmel River gage at Robles del Rio road
  26. Hydrologic Engineering Center for the US Army Corps of Engineers
  27. HEC-HMS Technical Reference Manual
  28. Schulumberger Water Services Westbay System-Monitoring Software
  29. Tasier Modeling Software
  30. Carmel River Lagoon and Potential Effects of Groundwater Extraction
  31. Environmental Tracers--a case study
  32. Tracers and Aquifer Recharge
  33. management of groundwater management resources in the Salinas Valley, California, by computer


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