Stream Recovery Model

A Model for Recovery of Stream Function through Hydrologic Reconnection (PDF-81 K)
Eddie Harris, October 2003

The model for recovery of stream function is presented for consideration as a basis for long range watershed master planning within urbanized areas on the south coast, where soil types and conditions are suitable. It reflects a recovery strategy that applies to local watersheds. The semi arid climate, short, steep, flashy upper watersheds, the alluvial flood plain, the densely urbanized landscape, and local geology are among factors that make south coast watersheds unique. Solutions to our watershed problems cannot be borrowed from other regions. They must be crafted for local needs, and must reflect local conditions. Solutions must arise from the understanding that in this region every drop of water that we receive from the sky must be carefully managed. Solutions must be based on science that has local applicability, where runoff from infrequent but sometimes very intense storm events bypasses the soil and the land, due to proliferation of paving and rooftops and gutters and storm drains that divert water directly into creeks and rapidly disperse it to the sea.

The model is intended:

• To illustrate how sustainable groundwater resources may be restored within a densely populated watershed.
• To illustrate how summer base flows in urban streams may be reestablished.
• To illustrate how efficient transport of sediments and suspended particulates during the summer months may be achieved.
• To focus on the full range of problems and deficiencies that plague our urban coastal streams.

Improving water quality, rehabilitating stream conditions for important species, and restoring biological productivity within aquatic systems are among the benefits and services of water resources that are addressed.

Other important tasks and programs that local agencies are charged with may benefit from implementation of strategies based on the recovery model. For example, fire risks may be addressed by ensuring that fuel moistures in riparian vegetation are maintained in a safe range. The crafting of Creek development standards may be simplified by allowing quantifiable performance objectives to be applied throughout creek buffer zones. Reliability and quantity of safe water supplies for domestic, irrigation, and industrial use may be enhanced. Flooding risks may be addressed by storing and slowly releasing water that results from heavy rainfall events.

The model is for evaluation by those who are interested. Local planners, decision makers, property owners, the general public, and those who may have expertise in the related disciplines are invited to study and discuss its applicability, and to consider it's usefulness in solving environmental problems on the south coast. Your comments and feedback are welcome.