LAKE ELSINORE WETALNDS ENHANCEMENT PROJECT
The State Water Resources Control Board provided a voter approved Proposition-40 Grant of $600,000 to the Lake Elsinore/San Jacinto Watersheds Authority (LESJWA) for the purpose of implementing an efficient and cost effective Best Management Practices (BMP) strategy to help address Lake Elsinore’s nutrient Total Maximum Daily Load (TMDL) to improve water quality. The City of Lake Elsinore is the local lead agency implementing the project.
The project created 2,800 linear feet of riparian shoreline and approximately 18,000 linear feet of new island shoreline for subsequent planting to expand riparian and aquatic vegetation and wildlife habitat in the existing wetlands area. Biodiverse aquatic ecosystems are known to improve water quality by utilizing nutrients and providing shelter for large bodied zooplankton that filter-feed on algae.
The cost of nutrient control, primarily phosphorus, throughout the entire Lake Elsinore/San Jacinto River Watershed to the degree required to meet federal/state water quality targets for Lake Elsinore may be unachievable and cost prohibitive. Alternatively, a combination of limiting nutrients in the watershed to the maximum extent practicable, lake aeration, lake-level stabilization and biomanipulation of the food web and vegetative community may be the most rapid and low cost approach to achieve the water quality targets.
Traditionally, excess nutrients have been determined to be the sole causal variable(s) that result in a biostimulatory response to produce nuisance algae blooms. This simplistic view that chemicals solely determine the biological response overlooks the complex interaction of the aquatic food web in regulating algae biomass through predator-prey interactions. Limnologist recognize there are two types of stable states for nutrient enriched shallow lakes, like Lake Elsinore, that result in very different environmental outcomes. One stable state is like the current condition of Lake Elsinore, in which the vegetative community is dominated by single-celled planktonic algae (like blue-green algae) and the fishery is dominated by planktivores (bait fish like, Threadfin Shad minnows and rough fish, like Carp). This stable state is characterized by turbid water, low dissolved oxygen, fish kills (especially sport fish) and swamp type odors.
In contrast, the more desirable second type of stable state for the same nutrient enriched lake is one dominated by true aquatic plants and piscivores (sport fish). This stable state is characterized by clear water, abundant zooplankton and a high number of sport fish. The key to this stable state’s desirable outcome is the high density of large bodied zooplankton that filter feed on algae, as well as the beneficial shelter and sequestering of nutrients by aquatic plants.
The project consisted of several phases, as picutured below.
1. Dewatering of Project Site.
2. Excavation & Earthwork.
3. Hydroseeding with Native Seed Plants.
4. Planting Native Plants by the volunteers from the Church of Jesus Christ of Latter Day Saints.
5. Reflooding of Wetlands.