Earlier this week I was out looking at salmon streams with Sheila O’Shea of SPAWN http://www.spawnusa.org/ . San Geronimo Creek rises in a mostly rural / suburban area west of Fairfax in Marin County. It is a tributary to Lagunitas Creek whose flow is now the controlled spill from Kent Lake Reservoir. These are salmon streams with no salmon (Coho) in them because the water levels are so low – northern California is experiencing a drought – and the Coho are apparently milling around getting fat in Tomales Bay waiting for their break and trying not to get eaten by sea otters. Two years ago the salmon had already returned by December.
While the drought is producing the absence of salmon right now even in a wet year clearly the urbanization of Marin affects the salmon habitat. Lagunitas Creek below the dam has adequate flow, points out Sheila, but it is too fast, and were the salmon to come up they would have a hard time finding the pockets of slower water in which to lay their eggs. And urbanization around San Geronimo Creek causes sudden runoff during rain, potentially producing mini “flash floods” with lower flows in between rains, which could potentially sweep away eggs or reduce oxygen in the water.
Natural areas do not exist in isolation. At the same time as a conservation plan is developed for the specific ecological areas, performance standards for the wider landscape that affects the ecological area – in this case the watersheds of the two creeks or the master plan area of a land development project – should be set to ensure that ecological systems upon which the natural area depends will continue (be sustained) or be enhanced. Such performance standards could be set by the municipality or other higher government authority and encoded as policy, and for a land development project required of the developer as a condition of approval for development.