Assessing Nassau County's Water Conservation Program

Abstract

To assess the effectiveness of Nassau County's water conservation program, the effects of population changes and weather patterns on water use must first be screened out. Using multiple linear regression, an equation was developed to predict average monthly pumping based upon the number of households in the county and two weather‐related indexes. The first index represents degrees over 65°F of the maximum daily temperature summed for each month. The second index represents consecutive days without rain, summed for the month. Using data for the period 1951–1986, a regression equation was developed describing total monthly pumping as a function of the number of households and the logarithm of the product of the two weather indexes. A Pearson correlation coefficient of 0.95 was attained. The equation was used to “project” pumping between 1987 and 1992, during which time a water conservation program was established. By comparing projected pumping with actual pumping over the period, the effect of water conservation could be estimated. Results indicate that the conservation program achieved a maximum one‐year decrease in water use of 11%.