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| Niles Cone aquifer | |
|---|---|
| Name | Niles Cone aquifer |
| Location | Alameda County, California, Hayward, California, Union City, California |
| Type | Aquifer |
| Operator | Alameda County Flood Control and Water Conservation District, East Bay Municipal Utility District |
Niles Cone aquifer The Niles Cone aquifer underlies parts of Alameda County, California and spans near Hayward, California, Fremont, California, and Union City, California. It functions as a primary groundwater resource for municipalities and industries connected to San Francisco Bay infrastructure and regional water agencies such as East Bay Municipal Utility District and Alameda County Flood Control and Water Conservation District. The aquifer’s management intersects with regional projects including the Hetch Hetchy Project, State Water Project, and local flood control planning by the Alameda County Flood Control and Water Conservation District.
The Niles Cone aquifer occupies a depositional plain fed by fluvial deposits from the San Joaquin River, Calaveras River, and local streams draining the Diablo Range, adjacent to San Francisco Bay, Mission San Jose watershed areas, and urban corridors like Interstate 880 and California State Route 84. Recharge sources include managed infiltration near facilities operated by East Bay Municipal Utility District, stormwater captured under programs coordinated with Alameda County Flood Control and Water Conservation District and managed return flows linked to San Francisco Public Utilities Commission infrastructure. Hydrologic boundaries interact with engineered levees, tidal influences from San Francisco Bay, and groundwater-surface water exchanges near Don Edwards San Francisco Bay National Wildlife Refuge. Regional groundwater flow models used by entities such as the United States Geological Survey and California Department of Water Resources describe hydraulic gradients, transmissivity, and storage across the Niles Cone system in coordination with urban plans from City of Hayward, City of Fremont, and City of Union City.
Geologic framework derives from late Pleistocene and Holocene alluvium, coarse-grained fan deposits from the Diablo Range, and interbedded finer sediments mapped in studies by the United States Geological Survey and California Geological Survey. Principal aquifer units show high permeability in gravel and sand layers linked to ancestral channels from Mission Creek and similar drainages, underlain by lower-permeability silts and clays correlated with stratigraphy documented near San Lorenzo Creek and Coyote Hills. Hydraulic properties—specific yield, porosity, and hydraulic conductivity—have been characterized in reports by the United States Geological Survey, California Department of Water Resources, and local utilities; these parameters guide pumping schedules for municipal wells managed by East Bay Municipal Utility District and groundwater sustainability projects aligned with the California Sustainable Groundwater Management Act.
Water quality in the Niles Cone aquifer has been affected by historical agricultural runoff, urban stormwater, industrial discharges tied to sites regulated by California Environmental Protection Agency, and legacy contamination from petroleum operations near Interstate 880 corridors and former rail yards associated with Southern Pacific Transportation Company rights-of-way. Constituents of concern documented by the United States Environmental Protection Agency and California Water Boards include nitrate, volatile organic compounds historically regulated under programs linked to Comprehensive Environmental Response, Compensation, and Liability Act frameworks, and salts concentrating from groundwater extraction influenced by tidal exchange with San Francisco Bay. Managed aquifer recharge and blending strategies have been coordinated with agencies including East Bay Municipal Utility District, Alameda County Public Works Agency, and regional water quality programs administered by the San Francisco Bay Regional Water Quality Control Board.
Groundwater extraction from municipal and private wells supports potable supply for districts such as East Bay Municipal Utility District and local municipal water departments in Fremont, California and Hayward, California. Management integrates conjunctive use with imports from the State Water Project, transfers under agreements involving the Metropolitan Water District of Southern California in broader regional trades, and local groundwater recharge projects implemented with partners like Alameda County Flood Control and Water Conservation District. Infrastructure includes wellfields, injection basins, and treatment facilities overseen by municipal agencies and coordinated with regional planning entities such as the Association of Bay Area Governments and the San Francisco Bay Conservation and Development Commission.
Development of the Niles Cone aquifer as a municipal resource accelerated during 20th-century urbanization connected to rail and road corridors built by Southern Pacific Transportation Company and related industrial growth in Alameda County, California. Early groundwater studies were undertaken by the United States Geological Survey and California Department of Water Resources; municipal well construction and managed recharge projects expanded after mid-century planning by regional water agencies including East Bay Municipal Utility District and local public works departments. Land-use changes tied to annexations by the City of Fremont and suburbanization following construction of Interstate 880 and the Dumbarton Bridge influenced recharge dynamics and regulatory oversight evolving through policies from the California Water Boards and later statewide frameworks like the California Sustainable Groundwater Management Act.
Groundwater level changes and quality shifts influence wetlands and remnant tidal marshes within the Don Edwards San Francisco Bay National Wildlife Refuge and habitats supporting species listed under the Endangered Species Act, with stakeholders including U.S. Fish and Wildlife Service and local conservation organizations. Saltwater intrusion linked to overpumping can alter salinity regimes affecting estuarine ecosystems documented by researchers at institutions such as University of California, Berkeley and San Jose State University. Urban stormwater and legacy contaminants intersect with habitat restoration work by agencies like the California Coastal Conservancy and nonprofit partners in the San Francisco Bay Trail corridor.
Monitoring networks maintained by the United States Geological Survey, California Department of Water Resources, East Bay Municipal Utility District, and Alameda County Flood Control and Water Conservation District track groundwater levels, water quality, and trends relevant to compliance with the California Water Boards requirements. Restoration and conservation initiatives include managed aquifer recharge pilot projects, saltwater intrusion barriers, and coordination with regional programs administered by the Association of Bay Area Governments and San Francisco Estuary Institute to protect aquifer sustainability and estuarine habitats. Collaborative frameworks engage municipal agencies, state regulators, and federal partners such as the U.S. Fish and Wildlife Service to integrate groundwater management with landscape-scale restoration in the San Francisco Bay region.
Category:Aquifers of California