Alhambra Creek, Alhambra Avenue, Alhambra Valley Road, Stock Pond, Vaca Creek
The Alhambra Valley Creek Coalition (AVCC) Restoration Project will stabilize severe erosion along a 1-mile reach of Alhambra Creek and at a headcut that threatens to undermine a dam in the upper watershed; enhance riparian habitat by replacing invasive plants with species native to the watershed; improve fish passage and in-stream habitat for native steelhead trout; restore two springs in the upper watershed, and reduce flooding by increasing channel capacity. Bank erosion along this reach is of particular concern because it threatens the gravesite of John Muir, located on National Park Service property. Further, residences on the entire reach are on septic systems; their leachfields are being exposed and are contributing to high bacterial levels in the creek. AVCC is the result of a coming-together of 47 neighbors interested in addressing their individual bank erosion concerns with a watershed approach. The innovation displayed by AVCC will be a leading example for creekside property owners across the state.
Project location: Alhambra Creek from Alhambra Avenue to Alhambra Valley Road (1-mile); Stock Pond and two springs near Vaca Creek, a tributary of Alhambra Creek (on Sky Ranch, owned by Muir Heritage Land Trust)
Purpose/Goals: The Alhambra Valley Creek Coalition (AVCC) Restoration Project will stabilize severe erosion along a 1-mile reach of Alhambra Creek and at a headcut that threatens to undermine a dam in the upper watershed; enhance riparian habitat by replacing invasive plants with species native to the watershed; improve fish passage and in-stream habitat for native steelhead trout; reduce flooding by increasing channel capacity; enhance upper watershed habitat by restoring native plants at two springs.
The goals of the project are to: (1) Improve water quality by reducing excessive erosion/sedimentation on Alhambra Creek and in the upper watershed, and preventing septic tank leachfields from being exposed to the creek; (2) Restore habitat for native species, including steelhead trout and red-legged frog that occur in the watershed; and (3) Alleviate flooding by improving creek access to its floodplain; and (4) Remove invasives and plant native plants (5) Prevent erosion from damaging John Muir's gravesiste; and (6) Enhance creekside elementary school environmental studies site.
Need/Critical impacts: Severe in-stream erosion (bank failure and downcutting) along a 1-mile stretch of Alhambra Creek. Creek incision is due to channel constriction, hardscape on banks, and lack of creek access to its floodplain. These conditions generate high shear stresses on the banks. Erosion of creek banks threaten the gravesite of John Muir on National Park Service land and is exposing septic system leachfields. 85% of banks in this reach are affected by invasive plants. This reach of Alhambra Creek erodes an estimated 250 cubic yards of soil annually. We expect to reduce this by 50% through bank stabilization and restoration of proper channel geometry. The ambient level for enterococcus in Alhambra Creek is 3 times the EPA standard for "infrequently used contact recreation." This problem will only worsen as bank erosion encroaches septic system leachfields. Mapping of this reach by volunteers has identified extensive infestation with invasives such as Arundo and ivy. John Swett Elementary which borders the creek has an active eco-literacy program. At present, it is conducted on campus - this project would improve safe access to the creek and allow the program to expand to also use Alhambra Creek as an educational resource.
In the upper watershed, a headcut along a stock pond spillway threatens the integrity of the entire structure. The pond is located at Sky Ranch - property owned by the Muir Heritage Land Trust. The problem stems from faulty design, poor construction, and soil compaction. The cut is about 100 feet long and appears to advance 6.5 feet/year. 247 cubic yards of soil has eroded away threatening the dam. It is advancing at a rate of 6-7 feet per year, which translates to approximately 16 cubic yards of annual sediment load that this project will eliminate. If the headcut is left unchecked and causes failure of the dam, it would trigger a much greater erosion problem and result in loss of the stock pond which benefits red-legged frog.
Native Plants, Flood Protection, Invasive Species Removal, Fish Passage, Channels, Bank Erosion, Habitat Protection, Habitat Enhancement, Steelhead, Creeks
Ecosystem Restoration,
Environmental and habitat protection and improvement,
Flood management,
NPS pollution control,
Storm water capture and management,
Water quality protection and improvement,
Wetlands enhancement and creation
