A Simple Method for Predicting the Capacity of a Lake for Development Based on Lake Trophic Status

Abstract

A general technique is presented for calculating the capacity of a lake for development based on quantifiable relationships between nutrient inputs and water quality parameters reflecting lake trophic status. Use of the technique for southern Ontario lakes is described. From the land use and geological formations prevalent in a lake’s drainage basin, the phosphorus exported to the lake in runoff water can be calculated, which, when combined with the input directly to the lake’s surface in precipitation and dry fallout, gives a measure of the natural total phosphorus load. From the population around the lake, the maximum artificial phosphorus load to the lake can be calculated and, if necessary, modified according to sewage disposal facilities used. The sum of the natural and artificial loads can be combined with a measure of the lake’s morphometry expressed as the mean depth, the lake’s water budget expressed as the lake’s flushing rate, and the phosphorus retention coefficient of the lake, a parameter dependent on both the lake’s morphometry and water budget, to predict springtime total phosphorus concentration in the lake. Long-term average runoff per unit of land area, precipitation, and lake evaporation data for Ontario provide a means of calculating the necessary water budget parameters without expensive and time-consuming field measurements. The predicted spring total phosphorus concentration can be used to predict the average chlorophyll a concentration in the lake in the summer, and this, in turn, can be used to estimate the Secchi disc transparency. Thus, the effects of an increase in development on a lake’s water quality can be predicted. Conversely, by setting limits for the "permissible" summer average chlorophyll a concentration or Secchi disc transparency, the "permissible" total phosphorus concentration at spring overturn can be calculated. This can be translated into "permissible" artificial load, which can then be expressed as total allowable development. This figure can be compared to the current quantity of development and recommendations made concerning the desirability of further development on the lake.

Water Quality Quantification: Basics and Implementation

“…The most well-known and widely-used example of the relationship between WQ (expressed as chlorophyll concentration) and management measure (as phosphorus loading) is the Vollenweider-Dillon-Rigler concept relating phosphorus loading to the bioproductive parameters of a lake (Vollenweider, 1976;Dillon and Rigler, 1975). Such dependences are statistical and applicable to a given type of lakes, and therefore they have relatively high uncertainties for individual lakes.…”

The areal hypolimnetic oxygen deficit: An empirical test of the model1

“…Principal data sets included in this analysis were presented by or summarized by Burns (1976), Decvey (1940), Dillon and Rigler (1975), Dillon et al (1978), Fish (1970), Lasenby (1975, Rast and Lee (1978), Schindler (1971), Snodgrass (1974), Stockncr and Northcote (1974), Vollenweider (1968), and Vollenweider et al (1974). A complete listing of the data is available on request.…”

The application of a phosphorus mass balance model for estimating the carrying capacity of Lake Kariba

“…R: Phosphorus retention coefficient is calculated from the equation below (10), where ρ = flushing rate (year -1 ): R = 1/1 + 0.75ρ 0.507 . Acceptable total P loading (L a ) is estimated by multiplying L fish and lake surface area.…”