Sand Mining in California's Central Coast Region

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An environmental summary created by the ENVS 560/L Watershed Systems class at CSUMB.

This page gives a short history of sand mining in California's Central Coast Region and highlights the CEMEX Lapis Plant. The page does not discuss gravel mining that occurs inland.


The only sand mining plant currently operating in California's Central Coast region, and the United States, is located in the City of Marina, Monterey County, California. The CEMEX Lapis Plant is located eight miles north of Monterey, California along Highway 1 and within the Lower Salinas River Watershed. [1]


Southern Monterey Bay Region in the Central Coast was the most intensively mined shoreline in the United States from 1906-1990. [2] The majority of sand mines were closed in 1990 due to assumptions that mining increased coastal erosion. The CEMEX Lapis Plant, located in the town of Marina, Monterey County, is the only sand mine in all of California that continues to operate. Best estimates suggest that the CEMEX plant mines nearly 326,000 tons of sand annually. [3] In 2016, the California Coastal Commission notified CEMEX of its intent to commence a cease and desist order for violations of the California Coastal Act. On 13 July 2017, the California Coastal Commission and CEMEX settled that Cemex will shut down operations by 31 December 2020 and avoid litigation. [4]. The agreement will end a more than century long era of sand mining in the Monterey Bay.

CEMEX Settlement Agreement

Events leading up to the agreement to shut down operations by 31 Dec 2020.

  • 2010 - The California Coastal Commission decided to look at CEMEX operations under the microscope following allegations from the public that the property owner was using bulldozers to push sand into the dredge pond. [5]
  • 2014 - The California Coastal Commission begins a series of meetings phone calls, and site visits with representatives of the CEMEX property owner. [5]
  • 2016 Mar 15 - The Marina City Council adopted a resolution authorizing the City Manager to request that the California Coastal Commissionn assist and coordinate with the City in any enforcement proceedings pursued in relation to possible violations of the California Coastal Act and the Marina Local Coastal Program by the CEMEX Sand Mining Operations. [6]
  • 2016 Mar 17 - The California Coastal Commission commences proceedings to issue a Cease and Desist Order and a Restoration Order for the imposition of administrative civil penalties and to resolve the violations of the Coastal Act resulting from unpermitted development that has and continues to occur on the CEMEX property. Unpermitted activities at CEMEX include dredging and extraction of sand, placement of floating dredges and development associated with the dredges (installation of anchors, cables, pipes, and pump station(s), grading, and changes in the intensity of use of the mine. [5]
  • 2017 Feb 3 - Marina City Mayor, Bruce Delgado sends a letter to the State Lands Commission urging the agency to assert its jurisdiction and require that CEMEX obtain necessary permitting from the State Lands Commission for any continued sand mining activity. [6]
  • 2017 May 16 - The State Lands Commission issued a letter to CEMEX indicating that CEMEX must either immediately submit a lease application or cease dredge pond operations because of the financial and resource impacts of its operations on the state. Specifically, the State Lands Commission noted that “the intensity of sand extraction at the Lapis operation causes environmental damage, public and private property damage, and loss of economic benefit through beach erosion.” [5]
  • 2017 June 6 - The Marina City Council adopted a resolution to find the CEMEX mine meets the elements required to be considered a public nuisance. [6]

Systems and Processes

Image 1. CEMEX Lapis sand mine (Monterey County Weekly, Karen Loutzenheiser, Mar 24, 2016.
Image 2. An undated photo of the CEMEX Lapis Sand Mine in Marina. Gary Griggs, PH.D, UC Santa Cruz.

Sand is a valuable part of the coastal land and dune ecosystem and is not a renewable resource. [7] The Monterey Bay tidal system moves sand along the shore, therefore sand removed from one location impacts the entire shoreline.[8] Sand in the CEMEX Pond, a 1,000 square feet artificial lagoon or "sink" in the shoreline, comes from the littoral sand supply of the Southern Monterey Bay (SMB) Littoral Cell. Every year, the ponds fill with sand carried by winter waves or wind. Sand mined from the Pond is removed directly from the cell and the cycle repeats. CEMEX mines an estimated 326,000 cubic yards of sand per year and removes roughly 50 percent or more from the littoral system and sand budget. [3] Between 1986 to 2013, CEMEX mined more than 6.8 million cubic yards (8.4 million tons) of sand that will never return to the coastal system. Sand mining is one of two major regional activities that have changed the sand supply into the SMB Littoral Cell. Historically, the Salinas River contributes sand to the cell however, dams on the Salinas River and movement of the river mouth have reduced the amount of sand brought into the SMB Littoral Cell. [9] The amount of sand removed by CEMEX vastly exceeds the amount of coarse-grained added into the cell from the Salinas River. Furthermore, CEMEX mines sand that originates from the Salinas River.

A general argument is that mining diminishes sand deposits on beaches and accelerates coastal erosion. Sand mining in coastal dune systems can lead to long term erosion of approximately 0.5 to 1.5 meters per year. [10] The southern Monterey shoreline on average is the most erosive shoreline in California [11].

Erosion Rates in Southern Monterey Bay[12]:

Monterey: 1 ft / year

Seaside: 3 ft/year

Marina: 6 ft/ year

Should mining from the CEMEX Pond stop, reductions in erosion and dune retreat are expected as more sand would be contributed to the littoral cell and move down the coast. <ref="memo"/>

Laws, policies, & regulations

CEMEX claims that because its operation precedes the California Coastal Act of 1976, it had vested rights to continue mining sand without acquiring further permits. [6] However, the California Coastal Commission found that the illegal dredge pond on site and an increase in extraction activity overstep the bounds of the vested rights. [5]. According to the California Coastal Commission, [9] mining sand from the beach at Marina conflicts with the Coastal Act in the following ways:

  • Impacts on the local sand supply, in conflict with Section 30235.
  • Habitat degradation and landform alternation, in conflict with Section 30231, 30240, and 30251.
  • Visual intrusion to the beach environment, in conflict with Section 30251.
  • Degradation of sand dunes creates a barrier to beach access, in conflict with Section 30211.

The agreement for the closure of the plant has several conditions for the future of the property, including a restricted deed so that the land must be purchased primarily for conservation purposes and will include public access. [4]

The City of Marina put out a request for proposals for a Local Coastal Plan update, in which one task includes drafting a vision for the reuse of CEMEX sand mine. [13]

Resources At Stake

Excavation of approximately 200,000 tons of sand each year can impact the following resources along the Monterey Bay shoreline:

  • Sand
    • A valuable resource that is used to make glass, computer chips, in cement to build houses and roads, and more. [14]
    • Provides protection from extreme conditions (i.e. flood, large storms, sea level rise)
  • Water supply
    • Sand mining can extend so deeply that it affects ground water, springs, underground wells through lowering of the water table. [15]
  • Species Biodiversity
  • Sub-tidal Habitat (Rocky Reef, Kelp forests, eelgrass beds)
  • Coastal/Sandy Beach habitat
  • Dune Habitat
  • Infrastructure
  • Public access of beaches and dunes for recreational use.
    • Existing Coastal Development (hotels, condos, etc.)
    • Highways & Bridges
  • Special Status Plants known to occur on the CEMEX property - sandmat manzanita (Arctostaphylos pumila), Monterey spineflower (Chorizanthe pungens var. pungens), sand-loving wallflower (Erysimum ammophilum), Menzies' wallflower (Erysimum menziesii), Monterey gilia (Gilia tenuiflora ssp. arenaria). [16]
  • Special Status Animals known to occur on the CEMEX property - black legless lizard (Anniella pulchra nigra), western snowy plover (Charadrius alexandrines nivosus), Smith's blue butterfly (Euphilotes enoptes smithi), bank swallow (Riparia riparia). [16]
    • In December 2014, CalAm began work on a test slant intake well located at the CEMEX sand mining facility in North Marina [17]. Due to the presence of threatened Western Snowy Plover breeding grounds near the test slant well, the location had to be returned to its original conditions by February 28, 2015 [18].


Various private and public organizations have interests in sand mining. Some of these are:

Local Government


  • CEMEX - Mexico-based, global building materials company which owns the CEMEX Lapis Plant in Marina, CA. [19]




Coastal Retreat in California's Central Coast Region, specifically Southern Monterey Bay, has the fastest rate of erosion in California.[11] Since the retreat is occuring in the Monterey Bay National Marine Sanctuary, scientists are determined to find possible mitigation efforts, reasons for high rates, and, specific hot spots.

Recent research includes:

  • Thorton et al. (2006) looked at sand mining impacts on long-term dune erosion in southern Monterey Bay [2]
  • Storlazzi and Field (2000) studied sediment distribution and transport along the Monterey Peninsula and Carmel Bay [20]
  • Coastal Regional Sediment Management Plan For Southern Monterey Bay prepared by Williams et al. (2008). [21]
  • Hapke et al. (2006) wrote the National Assessment of Shoreline Change Part 3: Historical Shoreline Change and Associated Coastal Land Loss Along Sandy Shorelines of the California Coast [11]


There are a variety of tools that can be used to assess the effects of sand mining and/or coastal retreat.

  • ArcGIS and the Digital Shoreline Analysis System (DSAS) toolbox can be used to monitor changes in beach width.
  • Stereo Photogrammetry [2]
  • LIDAR Measurements [2]
  • GPS Surveys [2]
  • Historical aerial photography

Future research

The Coastal Regional Sediment Management Plan for Southern Monterey Bay lists potential ways to address the issue of coastal erosion.

Continued study of beach erosion rates in the Southern Monterey Bay after the shutdown of the CEMEX plant will help confirm the impacts of sand mining. CSUMB is planning to continue erosion studies at the site.

CEMEX In The News


  1. CEMEX Lapis Plant
  2. 2.0 2.1 2.2 2.3 2.4 Thornton et al. 2006. Sand Mining Impacts on Long-term Dune Erosion in Southern Monterey Bay. Marine Geology 229.1:45-58.
  3. 3.0 3.1 An Evaluation of the Ongoing Impacts of Sand Mining at the CEMEX Lapis Sand Plant in Marina, California on the Southern Monterey Bay Shoreline
  4. 4.0 4.1 [ California Coastal Comission. 2017. CONSENT SETTLEMENT AGREEMENT AND CEASE AND DESIST ORDER CCC-17-CD-02. State of California Natural Resources Agency.]
  5. 5.0 5.1 5.2 5.3 5.4 Notification of Intent to Commence Cease and Desist Order and Restoration Order Proceedings and Administrative Civil Penalties Proceedings
  6. 6.0 6.1 6.2 6.3 Finding the current operation of the CEMEX mine meets the elements required for a Public Nuisance
  7. [1]
  8. Sierra Club - Beach Erosion caused by CEMEX sand mining in Marina
  9. 9.0 9.1 Coastal Processes affecting the Southern Monterey Bay (SMB) Littoral Cell With focus on the CEMEX Mine at Marina, CA
  10. [2]
  11. 11.0 11.1 11.2 Hapke CJ et al. 2006. USGS. National Assessment of Shoreline Change Part 3: Historical Shoreline Change and Associated Coastal Land Loss Along Sandy Shorelines of the California Coast
  12. California Coastal Erosion Response to Sea Level Rise
  13. [ City of Marina.2017. Request for Proposals. Local Coastal Plan Update Preparation of Sea Level Rise Vulnerability Assessment, Risk Assessment, and Adaptation Planning.]
  14. Sand Wars Movie Website
  15. Environmental Impacts
  16. 16.0 16.1 CEMEX: Ecological Resources
  17. In brief: Test slant well intake for Monterey Peninsula project now underway
  18. MPWSP Temporary Slant Test Well, Project Description
  19. CEMEX Website About Us Page
  20. Storlazzi, CD and Field, ME. 2000. Sediment distribution and transport along a rocky, embayed coast: Monterey Peninsula and Carmel Bay, California. Marine Geology 170.3: 289-316.]
  21. Coastal Regional Sediment Management Plan For Southern Monterey Bay



This page may contain student work completed as part of assigned coursework. It may not be accurate. It does not necessary reflect the opinion or policy of CSUMB, its staff, or students.