Calabazas Creek extends approximately 13.3 miles from the confluence with the Guadalupe Slough to the Saratoga foothills. Previous projects have provided flood protection on Calabazas Creek from San Francisco Bay up to Miller Avenue. This project completes the needed flood protection in the Calabazas Creek watershed. The watershed drains approximately 21 square miles within the cities of Sunnyvale, Cupertino, San Jose, Santa Clara, and Saratoga (see Figure 1). The proposed Project is along a 3.3 mile reach within the cities of Cupertino, San Jose and Saratoga. The area surrounding the project is part of the Santa Cruz Mountain foothills.
Calabazas Creek has three major tributaries within the project reach. Regnart Creek joins Calabazas Creek about 1000 feet upstream of Miller Road. Rodeo Creek joins Calabazas Creek 2,700 feet upstream of Bollinger Road. Prospect Creek joins Calabazas Creek at SPRR.
Most of the project reach is used for groundwater recharge by the Water District. Imported water from the Stevens Creek pipeline is released about one-quarter mile upstream of Prospect Road near the Union Pacific Railroad. The recharge zone usually extends downstream past Interstate 280 to about N. Tantau Avenue. Depending on the gravels in the creek, the released water may go below ground in some areas and re-surface further downstream.
The reach above Bollinger Road is where flood flows would flow out during the 1 percent flood. In fact, significant flooding occurred in the Project area (Calabazas Creek) in 1955, 1958, 1963, 1968 and 1998. More recently, in December of 2002, the area around Bollinger Road was flooded. During the 1955 flood, water poured into residential streets and homes, forcing the evacuation of more than 100 families. Flood waters inundated many of the same homes again in 1958. Without flood protection provisions, the 1 percent flood would inundate a large residential area bounded by Rodeo and Calabazas Creeks on the east, Saratoga-Sunnyvale Road on the west, and Regnart Creek on the north.
The portion of the project reach below Bollinger Road is a deeply incised water course with little distance between top of bank and the residential fence line. This reach experiences bank erosion problems. The creek above Bollinger Road is shallower, with some meanders, and has more trees along the banks. This reach has more room between the top of bank and the residential fence line and even has an access road in some locations.
Key features in the project area
There are several key features in the project area. Wilson Park is located about 500 feet upstream of the Regnart Creek confluence. Further upstream, just downstream of Rainbow Drive is the City of San Jose's Calabazas Park.
Meyerholz Public Elementary School is along the project reach between Bollinger and Rainbow Drive on the west side of the creek.
Union Pacific Rail Road (UPRR) is crossing Calabazas Creek just upstream of Prospect Creek. Highway 85 is crossing the creek 4,000 feet downstream of Prospect Road.