Conservation of the Lagoon and Marsh
The flora and fauna of Los Peñasquitos Lagoon and salt marsh obviously form a very different ecological unit from that of the upland portions of the Torrey Pines State Natural Reserve. At Present this flora and fauna is not as rare as that associated with the unique Torrey Pine trees; however, the fact that the coastal lagoans and marshlands of California are rapidly dwindling under the impact of urbanization has prompted the State Division of Parks and Recreation to raise the status of Los Peñasquitos Lagoon from “State Park” (with free public access and recreational use) to that of “State Reserve” (with restricted access and usage) and now to “State Preserve” (the most restricted usage). This label, which is pinned to only the rarest and most fragile of the state owned lands, reflects the increasing concern of ecologists and wildlife managers for the progressive destruction of coastal wetlands, a habitat vital for the preservation of migratory waterfowl and certain species of fish and shellfish.
The “Preserve” Status of Los Peñasquitos Marsh and Lagoon will ensure the future protection of the lagoon flora and fauna from direct public misuse. Unfortunately, however, the natural boundaries of the lagoon ecosystem do not coincide with the fence lines of the State Preserve, but extend upstream to the watersheds of the creeks draining into the lagoon and the tops of the mesas surrounding the marshland. Here, far outside the Preserve boundaries, the removal of brush may result in erosion and the subsequent deposition of huge loads of silt in the lagoon channels; similarly, a city many miles inland may discharge sewage effluent into a creek that flows into the lagoon and thereby cause an accumulation of unnaturally high concentrations of plant nutrients in the lagoon waters.
The lagoon is thus vulnerable to far reaching man-made changes in addition to local environmental alterations. Furthermore, the lagoon saltmarsh complex is an extremely fragile ecosystem, the life of which depends on the maintenance of a regular ebb and flow of tidal water. Excessive silting of the channels will hasten the closure of the lagoon mouth and will accelerate the filling-in of the marshland. Over enrichment of the lagoon waters will spark off unsightly algal blooms that lead to a syndrome of plant decay, oxygen depletion, fish kills, and unpleasant odors.
In March 1983, a Los Peñasquitos Lagoon Enhancement program began operation through cooperation of the California Coastal Commission and the Coastal Conservancy with assistance from the newly formed (and Conservancy approved) Los Peñasquitos Lagoon Foundation. Members of the Foundation board represent the State, City of San Diego, and San Diego County administration, as well as land developers and private environmental groups. The collection of an impact fee from applicants for building permits within Los Peñasquitos watershed, as a mitigation measure, had resulted in the state policy for protection and restoration of the lagoon and wetlands. In March 1985, the planned restoration was announced in the Los Peñasquitos Lagoon Enhancement Plan, a guidebook approved for implementation of state restoration policy.
The planned program has proceeded so that tidal action approaches the stated goals, with more extensive work projected into the future. Wetland acquisition has been achieved through state purchase of the 200+ acres of former San Diego Gas & Electric utility land which encompasses major lagoon channels into Torrey Pines State Natural Reserve. Other additions to the south include approximately 20 acres of valuable wetland in Sorrento Valley. Stewardship has been accepted for the 22 acre open space easement that extends from the Torrey pines Extension to the lagoon below, south of Carmel Valley Road.
The Foundation continues in its main function which is to keep the lagoon mouth open, monitor physical changes, restore habitat, and improve channel circulation.
In a geological sense, all lagoons are ephemeral because the filling-in of the marshlands and channels eventually leads to their conversion to dry land. The rate at which this filling process occurs, however, depends largely on the rate of silt deposition and accumulation of organic material in the lagoon. Los Peñasquitos Lagoon will not escape this ultimate fate, but a long remaining life span will depend on the foresight of the present generation of citizens who will determine whether this life span will be measured in thousands of years or merely a few decades.
Next topic: Lagoon bibliography