The City of Gilroy is the southernmost city in Santa Clara County and has a population of 41,464, based on the 2000 Census. Renowned for its garlic, Gilroy has a strong agricultural legacy which continues today.

Gilroy occupies a broad, gently sloping, fertile plain enclosed on the northeast by the Diablo Mountains of the Contra Costa range and on the west by the Santa Cruz Mountains. At the southern end, the Santa Clara Valley merges into the Pajaro Valley.

Shared Responsibilities

Most policies guiding development and use of resources in Gilroy are contained in the City's General Plan; specifically, the Community Resources and Potential Hazards section contains comprehensive policies pertaining to water quality. With the understanding that their roles and responsibilities often intersect, the District and the City work together on many key community interests. City goals and policies regarding water resources include:

  • Protecting creeks from urban encroachment and degradation
  • Protecting groundwater in the Llagas subbasin from contamination
  • Exceeding required and recommended standards for drinking water set forth by the State
  • Establishing land use controls prohibiting waste facilities and other sources of pollution near groundwater, floodwaters, creeks or reservoirs
  • Designing and implementing flood control measures in accordance with BMPs

Looking forward, further collaboration or partnership will facilitate sustainable development in the region, particularly in the following areas:

When evaluating land use decisions:

  • Assess and plan for changes in water demand and storm water management, especially taking into account how urbanization affects the water cycle.
  • Decrease the demand for water.
  • Expand water use efficiency in existing and new development.
  • Actively pursue and facilitate the use of recycled water.
  • Protect and expand local water supplies.
  • Protect groundwater basins and source water protection zones.
  • Reduce flood risk.
    • Site new construction to assure stable stream channels and minimize flood risk.
    • Require that new construction in flood prone areas be built to flood safe standards.
  • Protect natural stream functions.
    • Restore fisheries, riparian habitat, and wetland areas.
    • Explore opportunities for increased creek-side trails and open space.

During operations of existing facilities or services:

  • Manage local storm drainage systems with stream capacity to contain floodwaters.
  • Support measures to reduce the exposure to flood risk.
  • Support measures to enhance flood preparedness and knowledge of risk exposure.
  • Prepare critical facilities for operations during flood events or prolonged draught.
  • Reduce pollutants entering streams.


The interactive map below shows the location of Gilroy and illustrates some of the city's key features, such as major creeks, flood zones and groundwater subbasins.

To view key features, choose a layer from the "Select a layer to display" menu on the map below. You can select multiple layers to view at one time; if you wish to turn off a layer, select it again from the menu. Individual layers contain specific data that you can access by clicking on the layer itself.




Key Water Resources Features


Water Supply

The City's General Plan sets forth a goal of protecting "groundwater in the Llagas Subbasin from contamination and a clean and healthy supply of potable water in compliance with State and Federal water quality standards." In support of that goal, the City outlines a number of policies and actions, including inter-agency coordination with the District, the Regional Water Quality Control Board and others. The Plan also sets forth specific land use controls and monitoring programs to protect groundwater quality.

Gilroy advocates for water use efficiency by partnering with the District on water conservation and water recycling programs. The city promotes recycled water use at its own and non-municipal facilities. Along with Morgan Hill, it constructs and operates recycling facilities as part of the South County Regional Wastewater Authority.

Flood Protection

Gilroy addresses natural hazards in its General Plan and includes specific policies aimed at minimizing the potential for flooding and reducing flood damage. These policies include restricting development in flood-prone areas and on steep slopes, making use of natural channels for flood control and requiring new development to include green areas to absorb runoff. The Plan also presents an "Acceptable Risk" matrix that defines the level of risk that the public may be willing to assume for certain structures and locations.

Watershed Health

Gilroy seeks to preserve and protect riparian habitat and avoid adverse affects of development on local creeks. To that end, the General Plan sets forth policies requiring minimum set backs along the Uvas and Llagas creeks to establish adquate buffer zones and allow adequate room for trails and access. Any open space development is subject to an environmental review process to determine if it is compatible with natural processes. 


Citywide Programs and Projects

The City and the District collaborate on projects to maintain the health of the watershed and water quality, establish natural flood protection and provide access to open space and trails. Recent programs include:


Related Plan Elements

The Related Plan Elements listed below identify some of the District strategies  applicable to the city. They provide the basis for cities to provide better management of key water resources features within their jurisdictions and to work more effectively with the District to address water resources managemenet issues.

Related Plan Elements

District Has Primary Jurisdiction
E- Maintain the design floodwater conveyance capacities within District-owned channels. (P)
District Collaborates
E- Include municipal planners in regional or local flood management planning activities. (C)
District Advocates
E- Promote removal or abandonment of infrastructure located within floodplains. (T)
District Advocates
E- Assist in the incorporation of flood-wise design features (e.g., minimize imperviousness, preserve natural drainage, rain harvesting and provide flood water detention) within the watershed. (T)
District Advocates
E- Encourage and provide technical assistance in mitigating erosion, sedimentation and high flows from new development or redevelopments. (T)
District Advocates
E- Promote awareness of risks for developing in flood hazard areas. (T)
District Collaborates
E- Identify and incorporate stream rehabilitation measures into capital projects and operations to avoid, minimize and/or impacts to watersheds, streams and natural resources. (P and C)
District Advocates
E- Provide information on stormwater management and design of floodplains and channels. (T)
District Collaborates
E- Engage in habitat conservation planning.(P and C)
District Has Primary Jurisdiction
E- Protect groundwater recharge areas in creeks and riparian corridors. (P)
District Collaborates
E- Protect, enhance and restore riparian vegetation and in-stream and tidal habitat conditions conducive to healthy ecology, including diked historical bayland wetlands, or former salt ponds. (P and C)
District Collaborates
E- Protect, enhance, restore and/or create habitats for key species indicative of watershed health. (C)
District Advocates
E- Promote the protection and preservation of sensitive groundwater recharge areas. (T)
District Advocates
E- Promote protection, preservation and enhancement of creek and bay ecosystems functions. (T)
District Advocates
E- Promote the preservation of ecological buffers. (T)
District Has Primary Jurisdiction
E- Protect and preserve groundwater recharge areas.(P)
District Advocates
E- Promote the protection and preservation of sensitive groundwater recharge areas. (T)
District Advocates
E- Promote the preservation of riparian corridors and provide guidance supporting watershed health to the entire community. (T)
District Collaborates
E- Reduce pollutants in streams from urban runoff and minimize the effects on surface and ground water.
District Collaborates
E- Work with other entities for planning, design, construction, maintenance, and operation of trails/open space amenities.
District Collaborates
E- Increase public access to District lands as appropriate; extend trails network.
District Has Primary Jurisdiction
E- Support creek-side or water related recreation, as appropriate.