Water Quality - Effects of Aeration & Importing Water

One of the alleged benefits of LEAPS is the project's improvement of Lake Elsinore's water quality as a result of millions of gallons of water moving up and down the hill. While it is true aeration increases oxygen levels and helps prevent temperature-based stratification and low oxygen levels in deeper layers, aeration does close to nothing in the long-term to reduce the natural elements that cause cloudy greenish water: Nitrogen, potassium, and phosphorus from natural and man-made sources including agricultural / yard fertilizer runoff and septic systems are the main food source for micro flora - the tiny plant organisms that give the lake its color.


AERATION - ADDING OXYGEN - HAS LITTLE TO NO IMPACT ON NUTRIENT LEVELS

Studies by government environmental agencies and academic research institutions consistently show Lake Aeration has little to no impact on long-term Phosphorous levels in a shallow lake environment. Lake Elsinore has high phosphorous as a result of its water supply and also because it is not a fully-flowing lake, more like a long-term holding basin with no continuous in/out mechanism to regularly replace its water. Water flows into lake Elsinore and stays there. As lake water evaporates, concentrations of dissolved solids increase, temperatures increase and micro flora blooms occur.


TEMPERATURE RISE

A documented effect of aeration on shallow lakes, according to the experts, is an overall increase in lake temperatures resulting from mixing up of the cooler and warmer layers. Warmer waters combined with high nutrient concentrations can result in algae blooms and cloudy water. If aeration were a silver bullet, Lake Elsinore, which has been aerated for many years now, would look quite different.


TURBIDITY - PARTICULATES SUSPENDED IN WATER

Another potential side effect of moving such high volumes of water in and out of the lake is higher turbidity, or cloudiness, from disturbance of lake bottom solids/dissolved solids. If you have ever stepped on and disturbed the bottom in a clear lake or river and saw the resulting cloud of muck destroy visibility, imagine what moving millions of gallons will do to lake clarity over time. In addition, the complete effects of disturbing the Bottom of Lake Elsinore, in terms of what could be released into the water, are unknown.


MAIN CONCLUSIONS FROM THE 2006 WATER QUALITY STUDY BY M.A. ANDERSON OF UC RIVERSIDE:

ADDING WATER (EXTERNAL LOADING) ACCOUNTS FOR A SMALL PERCENTAGE OF PHOSPHOROUS CONTENT IN THE LAKE. IN OTHER WORDS, ADD ALL THE "HIGH QUALITY WATER" YOU WANT, THE HIGH PHOSPHOROUS LOAD IS BUILT-INTO THE LAKE SEDIMENT. 

 

"...First of all, the process of internal recycling dominates the annual loading of phosphorus to the water column of Lake Elsinore, even during years with very strong inputs from the San Jacinto River. 

Model results indicate that external loading contributed on average only 5.7% of the total annual P loading for the period from 1993-2004, while wind resuspension and bioturbation from carp typically accounted for 0.6% and 3%, respectively (Table 4). 


Even during the extreme runoff conditions of 1993, external loading was predicted to account for only 16.9% of the total annual P loading to Lake Elsinore. 


These statistics belie the impact of external loading on P concentrations and lake water quality, however, since externally loaded P is recycled a number of times and potentially over several years before it is finally buried. The lake does have some capacity to sequester P in the sediments, with about 15% of the P settling to the sediments thought to remain there...


...It appears that reducing external phosphorus loadings to the maximum extent practical, coupled with concerted efforts to reduce internal phosphorus loading rates through in-lake treatments is the best approach to consistently achieve water quality objectives."


NOT A WORD ABOUT ADDING WATER TO REDUCE PHOSPHORUS LEVELS. 


Below is just a small sampling of studies demonstrating the effects of aeration on lakes - Note the distinction between shallow lakes such as Lake Elsinore, and deep lakes, where water stratification by temperature layers is more pronounced and aeration tends to work better than in shallow bodies of water.