Guadalupe Creek



The Stewardship Plan for the Guadalupe Watershed planning area envisions the Guadalupe Creek Watershed as a reliable source of water supply with continued flood protection and groundwater recharge operations through existing percolation facilities.

This vision seeks to reduce the existing levels of mercury contamination and enhance the quantity and quality of riparian and aquatic habitat. The creek intends to sustain a steelhead community downstream of the reservoir. Natural channel stabilization techniques will be used, where possible. A network of trails will be completed, linking public lands in the south with urban lands in the north.

The District will guide land use planning toward protecting undeveloped streamside property and minimizing impacts of projected infill development in the lower watershed. Stakeholders will have an increased presence in environmental stewardship and will promote best practices to support watershed health and resources.


Key characteristics of the Guadalupe Creek Watershed:

  • From 1846-1975, the watershed was home to the largest mercury mining operation in North America, the New Almaden Mining District. Although physically located in the Alamitos Creek Watershed, the effects of mercury in the water and in fish assemblages poses the single largest ecological health concern throughout the South Bay communities.
  • The watershed has the highest percentage (92) of non-urbanized land of any in the planning area.
  • The watershed has the least amount of hardened channels than any other in the planning area.
  • The most prominent water feature in the watershed is the Guadalupe Reservoir, completed in 1935.
  • The watershed has the greatest amount of upland in the planning area.
  • Fish use the entire length of Guadalupe Creek.

Potential Partners and Collaborators

The District collaborates closely with other jurisdictions, agencies and stakeholders in and around the watershed to create healthy, livable environments. This collaboration is aimed at preserving and protecting the watershed through effective land use policies and programs.

The District coordinates with a number of key federal and state agencies in regulating and managing the Guadalupe Creek Watershed, including: Army Corp of Engineers; Federal Emergency Management Agency; Department of Water Resources; Department of Agriculture; National Resource Conservation Service; National Marine Fisheries Services; California Parks and Recreation; and California Fish and Game.

On the regional level, the District collaborates with agencies to ensure that projects and programs in the watershed are consistent with county-wide goals. Two key partners are: Midpeninsula Regional Open Space District, which guides open space preservation efforts; and the Santa Clara Valley Audubon Society, which emphasizes ecosystem restoration and wildlife conservation. In addition, the District coordinates with other regional efforts such as the Habitat Conservation Plan, the Santa Clara Valley Urban Runoff Pollution Protection Program (SCVURPPP) and the Fisheries and Aquatic Habitat Collaborative Effort (FAHCE).

Portions of the cities of San Jose and Los Gatos are situated in northernmost portion of the watershed. The southern two-thirds include unincorporated parts of Santa Clara County and are generally under the authority of the Midpeninsula Regional Open Space District and the County Park Department. Each jurisdiction’s general plan, zoning ordinance and other guiding documents establish their approach to flood protection, water quality, water supply, open space and recreation. The District works with each jurisdiction to ensure that overall programs and policies are compatible, effective and achievable.

In addition, the District also partners with various community groups to conduct stewardship activities in various creeks in the watershed. For example, Meritage Properties, Branham High School Octagon Club, Branham High School Recycle Club, Pioneer High School and Steinbeck Middle School have adopted parts of Guadalupe Creek. The District will continue to promote ongoing joint community partnership and advocacy opportunities.


Watershed Maps

The interactive map below shows the location of the Guadalupe Creek watershed and illustrates some of the area's key features, such as major creeks, flood zones and groundwater basins.

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. Individual layers contain specific data that you can access by clicking on the layer itself.



Location and Natural Settings

Guadalupe Creek Watershed is located in central area of the Guadalupe Watershed planning area. In addition to the Guadalupe Creek, the planning area consists of three other watersheds: Guadalupe River, Alamitos and Los Gatos.

The watershed originates at approximately 3,500 feet on the eastern side of Mount Umunhum in the Santa Cruz Mountains and has a drainage area of about 15 square miles. The creek joins Guadalupe River just north of Almaden Lake. As the principal drainage for the watershed, Guadalupe Creek is over ?? miles long

Guadalupe Creek Watershed has the greatest amount of natural channel of any other in the planning area. With the exception of a 500 foot concrete stretch near the confluence with Pheasant Creek, Guadalupe Creek is entirely earthen.

Geography in the watershed varies between the undeveloped mountains and the highly developed urban valley floor. Approximately 92 percent of the Guadalupe Creek Watershed is non-urbanized, including a significant array of parks, open space, rangeland and forests. The majority of this undeveloped land is found in the central and southern portion of the watershed. Nearly all of the eight percent urbanized land is residential and is found in the northernmost edge.

Although there are no active mines in the watershed, there were two limestone mines, one chromite mine and one stone mine. Additionally, several mercury mine companies once operated in the adjoining Alamitos Creek Watershed. Known as the New Almaden Mining District, the area is now part of the Almaden Quicksilver Park. The residual effects of mercury mining continues to have an impact on ecosystem health.

There are a number of faults in the Guadalupe Creek Watershed vicinity: The watershed is situated to the southwest of the Monte Vista Fault; the San Andreas Fault system is to the southwest of the watershed; the Berrocal Fault Zone is found in the Guadalupe Creek Basin.

Over the years, a number of efforts in the watershed have focused on environmental restoration and flood protection, including: Guadalupe Creek Restoration Project; Upper Guadalupe River Flood Protection Project; and Downtown Guadalupe River Flood Control Project.

The following photographs show the watershed at various locations along its course:

 Sample photographs from Guadalupe Creek


Key Water Resources Features

Water Supply

The water supply system in Santa Clara County includes surface sources (reservoirs, creeks and others) and groundwater found in aquifers.



In 1935, the Guadalupe Reservoir was completed with the construction of the Guadalupe Dam. Maintained and operated by the District, the main purpose of the reservoir is to capture runoff from winter storms to recharge in the Alamitos percolation pond system during the summer.

The reservoir has an average surface area of 79 acres, a capacity of 3,228 acre-feet and an approximately six square mile drainage area. Year round water sources to the reservoir include Rincon, North Los Capitancillos and Upper Guadalupe creeks.

Based on District reservoir management practices, a series of rules were developed to administer reservoir capacity and use. These rules take into account the various functions of the reservoir and include water temperatures needs, flood water storage needs, fish stream flow needs and minimum stream depth needs.


Major Creeks and Other Sources

Guadalupe Creek is the principal creek in the watershed, originating on the eastern side of Mount. Umunhum, above the Guadalupe Reservoir. The creek joins the Guadalupe River just east of Almaden Expressway. Primary tributaries include: Rincon, North Los Capitancillos, Hicks (also known as Cherry Springs), Shannon and Pheasant.

There is also an additional water conveyor. Originating at the west end of Calero Reservoir (Alamitos Creek Watershed), the approximately 12 mile long Almaden Valley Pipeline carries water from the Calero Pipeline to the Santa Teresa Main, or Vasona Pump Station in Los Gatos. Water via the Almaden Valley Pipeline can be diverted to the Alamitos percolation ponds.



The Santa Clara Valley Groundwater Basin consists of three subbasins: The Santa Clara Valley Subbasin in North County and the Coyote and Llagas Subbasins in South County. Stevens Creek Watershed provides groundwater for the Santa Clara Valley Subbasin. The District uses percolation ponds to support groundwater recharge and to reduce water loss.

The District has two sets of recharge ponds affiliated with the Guadalupe Creek Watershed: Alamitos and Los Capitancillos percolation ponds. The Alamitos percolation ponds (two) are adjacent to the District’s main headquarters and the Guadalupe River. Combined, the ponds have a surface area of 11 acres. The southern pond, originally the site of a gravel mining operation, was constructed in 1932 and reconstructed in 1963. The northern pond was constructed in 1976. Guadalupe Creek, Alamitos Creek and the Almaden Valley Pipeline supply water for the ponds.

Completed in 1962 and reconstructed in 1964, the Los Capitancillos percolation ponds (10) occupy about 63 acres, from Almaden Expressway (east) to Camden Road (west). Guadalupe Creek and the Almaden Valley Pipeline supply water for the ponds.

Completed in 1964, Masson Dam is a small diversion dam about 1.3 miles upstream of Almaden Expressway. The dam conveys water into the Los Capitancillos percolation ponds continually, unless Guadalupe Reservoir spills. If the reservoir spills, diversion operations terminate until the rainy season ends. A fish ladder for completed in 1999 at Masson Dam.


Watershed Health

In managing watershed health, a balance must be found between the needs of habitat protection, water supply, flood management and ecosystem restoration and the needs for housing, economic development and recreation.


Erosion and Landslides

Almost 90 percent of the Guadalupe Creek Watershed is within the eastern Santa Cruz Mountains, while the remaining area is in the Santa Clara Basin valley floor. Despite such a high percentage of upland, just over 70 percent of the watershed is considered low risk for erosion. The highly erodible areas are found in the southern portion, within the hills of the three creeks that drain to Guadalupe Reservoir. The reservoir captures sediment from potential erosion in this location.

Highly erodible hills are also found along Hicks Creek and in the headwaters of Shannon and Pheasant creeks. Here, sediment is deposited directly into the channels. In other upland areas of the watershed, stream banks and hills are largely forested. This vegetation helps stabilize the land against erosion and makes sediment contribution unlikely.

Landslide susceptibility in the watershed is considered to be high. About 16 percent of the area is characterized as mostly landslide. Hills on the western side of the creek, from below the Guadalupe Reservoir to the confluence with Pheasant Creek, have a high susceptibility to landslide and sediment would be deposited into the creek. Evidence of a large landslide is found in the southeast, along North Los Capitancillos Creek. As noted, the reservoir intercepts corresponding sediment.



The entire Guadalupe Creek channel is capable of conveying a 100-year flood event. The creek has only flooded once, in 1986.


Water Quality

Originating from mercury mining operations from 1846-1975 in the New Almaden Mining District (Alamitos Creek Watershed) contaminants continue to have an effect on the Guadalupe Creek Watershed and throughout the South Bay communities. Since fish with elevated mercury have been found in the Guadalupe Creek Watershed, fishing is only permitted in the watershed as “catch and release.” To address this issue, the District has established comprehensive fish advisories throughout the watershed. In addition, toxic sediment is regularly monitored throughout the watershed.

Guadalupe Creek Watershed is listed as impaired for mercury and diazinon.


Potential Development

Since so much of the Guadalupe Creek Watershed is non-urbanized protected open space, land use intensification will be minimal and will be confined to the existing urbanized areas. Potential development in the urbanized area will likely include residential infill, with limited neighborhood-serving commercial intensification. Consequently, the watershed is expected to experience an increase in the amount of impervious surface as infill development occurs. This increase may have a corresponding negative effect on flooding and watershed health. New creekside development will be encouraged to employ ecologically sensitive site design and construction to protect stream function and watershed health.


Environmental Stewardship


Riparian Habitat

Between Almaden Expressway and Camden Avenue, riparian habitat is predominately barren as the creek travels through a highly urbanized area. Upstream of Camden Avenue, particularly approaching the uplands, the prevailing riparian community is oak sycamore woodland.


Aquatic Habitat

Preliminary surveys suggest Guadalupe Creek has viable aquatic ecosystem to support warmwater and coldwater fish assemblage. The Guadalupe Reservoir, however, impedes anadromous fish passage. The canopy cover upstream of Camden Avenue provides ample cover, creating good quality aquatic habitat and shelter.

In 1999 the Masson Dam fish ladder was completed. Using this structure, species can climb the dam using a series of steps to navigate the changing creek elevation. This allows fish to travel upstream, where there is excellent fish rearing and spawning habitat.

District surveys include suitable habitat to support the red-legged frog, from Guadalupe River to the reservoir. There are numerous segments that support the western pond turtle. Also, below the reservoir the creek supports yellow legged frog, yellow warbler, double crested cormorant, steelhead and Chinook salmon. Recent records show support for Mt. Hamilton thistle, Santa Clara Valley dudleya (Endangered) Santa Clara red ribbons, fragrant frittilary and the most beautiful jewel-flower.


Trails and Open Space

Guadalupe Creek Watershed has approximately 22 miles of trails, notably the Juan Bautista de Anza National Historic Trail, Guadalupe Reservoir-Calero Connector Trail and the Bay Area Ridge Trail. Also, the Guadalupe River Trail parallels a sizeable portion of the creek as it continues north, linking to the San Francisco Bay and the Bay Trail. (Tim, the AQP web page cites 33 miles of trails in the park alone. Document says 22 in watershed?).

The Guadalupe River Park Master Plan designates three miles of pedestrian and bicycle trails along the river. A long-term goal of the Plan is to link trails along the river with trails north to Alviso and trails south to Almaden Valley. The Sierra Azul Open Space Preserve identifies potential trail opportunities, focusing on connecting creekside trail networks across watersheds.

Although trails are found along Guadalupe Creek below Camden Avenue and just below the reservoir, fences and gates impede public access. Despite the existing pattern of privately owned property, there are many opportunities for developing new trails and opening access to existing trails. In particular, developing a trail between Camden Avenue and the confluence with Shannon Creek would complete this gap and link areas north of the watershed to trails within the watershed.

The watershed contains an impressive amount of permanently-protected open space. Most of this open space is found in the central and southern portion of the watershed. A large portion of MROSD’s Sierra Azul Open Space Preserve is found along the foothills of the Santa Cruz Mountains and is largely accessible to the public. A portion of Almaden Quicksilver Park lies east of Guadalupe and North Los Capitancillos creeks. Newhagen Meadow is west of the reservoir and has restricted public access.

The Guadalupe Reservoir lies within the County of Santa Clara’s Almaden Quicksilver Park. Recreational activities include picnicking, hiking and fishing. However, fishing is only permitted as “catch and release” as the Department of Public Health deemed the fish unsafe for consumption due to elevated mercury levels in their tissue. Swimming, wading and powered boating are not permitted.


Browse the Framework

Related Plan Elements

District Has Primary Jurisdiction
E- Identify existing stream conditions and stream characteristics and implement practical solutions where appropriate, to improve stream stability and its dynamic equilibrium. (P)
District Advocates
E- Provide technical advice and, if appropriate, work with municipalities to manage stormwater to address stream flooding and environmental benefits. (T)
District Has Primary Jurisdiction
E- Maintain the design floodwater conveyance capacities within District-owned channels. (P)
District Advocates
E- Support and promote land use decisions to maintain stream capacity. (T)
District Collaborates
E- Assist municipalities and citizens when needed to lessen potential flood impacts. (C)
District Collaborates
E- Include municipal planners in regional or local flood management planning activities. (C)
District Collaborates
E- Ensure floodplain maps (alluvial and tidal) are based on best available data. (C)
District Advocates
E- Promote awareness of risks for developing in flood hazard areas. (T)
District Has Primary Jurisdiction
E- Balance the protection and restoration of sensitive fisheries and aquatic species, such as steelhead trout, with a reliable water supply. (P)
District Collaborates
E- Implement stream stewardship opportunities in capital and maintenance activities, including stream rehabilitation and environmental enhancements and seek to achieve the physical stability and ecological health of streams. (P and C)
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 Advocates
E- Promote the protection and preservation of sensitive groundwater recharge areas. (T)
District Has Primary Jurisdiction
E- Protect and preserve groundwater recharge areas.(P)
District Has Primary Jurisdiction
E- Improve water quality of listed impaired water bodies.(P and C)
District Collaborates
E- Promote the protection and preservation of water quality and providing stream stewardship. (C)
District Advocates
E- Promote the protection and preservation of sensitive groundwater recharge areas. (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 Has Primary Jurisdiction
E- Support creek-side or water related recreation, as appropriate.