A stretch of Llagas Creek in south Morgan Hill will soon be thriving with native plants and animals as Valley Water completes the largest wetland restoration project in the agency’s history.
As part of the Llagas Creek Flood Protection project, Valley Water has created the new wetland habitat at Lake Silveira, located in unincorporated Morgan Hill near San Martin. The project aims to restore steelhead habitat in Llagas Creek, according to Valley Water officials.
In the coming weeks, crews will plant more than 9,100 native trees, shrubs and other wetland vegetation to support the natural environment and wildlife of Lake Silveira and the restored section of Llagas Creek as winter rains approach.
“This is the largest wetland creation and stream restoration that Valley Water has ever done,” said Valley Water Director John Varela, who represents South County on the water district’s board. “A lot of freshwater wetlands in our valley have disappeared. This new wetland habitat will be a hidden gem once the lake fills with water, native plants grow, and the native amphibians, reptiles and fish return to the site.”
Lake Silveira was, in the 1970s, once the site of an active quarry that supported the construction of Highway 101, according to Valley Water staff. A previous landowner removed a levee from nearby Llagas Creek, forcing water into the quarry, creating Lake Silveira. The levee removal dewatered about 2,000 linear feet of Llagas Creek, which had flowed to the north of the quarry.
Llagas Creek is home to the federally threatened South Central California Coast Steelhead. The restoration at Lake Silveira includes re-establishing flow in the section of Llagas Creek which has remained without water for about 40 years while the flows were directed toward the lake, Valley Water staff said.
Water released from Chesbro Reservoir upstream began filling the lake and wetlands in late October. However, this water is expected to recede.
To restore the dry section of Llagas Creek and create the new wetland habitat, Valley Water relocated native fish, amphibians and reptiles before emptying the lake. Crews also removed 12.5 acres of invasive, non-native blackberries and prepared the site to plant thousands of native plants.
The new wetland habitat will help support the Western Pond Turtle, which is listed as “a species of special concern” in California, according to Valley Water staff. The project includes the construction of 10 large wooden structures within the lake “to allow the turtles to bask in the water while being protected from predators,” reads a press release describing the project. Valley Water also created islands within the lake as a wildlife refuge.
Lake Silveira will remain closed to the public while water, plants and animals return and grow in the newly restored wetland, according to Valley Water. However, the water district is working with the City of Morgan Hill to develop the site for recreation in the future.
The restoration work at Lake Silveira is just one portion of Valley Water’s Upper Llagas Creek Flood Protection Project, which consists of about 13.9 miles of flood protection improvements along East Little Llagas Creek, West Little Llagas Creek, and Llagas Creek within Gilroy, Morgan Hill and the unincorporated area of San Martin. When all phases of the project are completed, the project will provide flood protection for approximately 1,100 homes, 500 businesses, and more than 1,300 acres of agricultural land in southern Santa Clara County.
The creek restoration and wetland creation were completed to offset adverse impacts of the flood protection work along Llagas Creek.