Effect of land area on average annual suburban water demand

Abstract

Current guidelines for estimating the average annual residential water demand (AADD) in South Africa are based on residential plot size. This paper presents a novel, robust method for estimating suburban water demand as a function of the suburb area. Seventy suburbs, identified as being predominantly residential, were selected for analysis from the largest urban metropolitan area in South Africa. A linear relationship was noted between the total suburb water demand and two land cover areas, namely, the total suburb area and total residential plot area. The average demand for the 70 suburbs based on suburb area was 6.6 kℓ∙d⁻¹·ha⁻¹, with 90% of the values in the range between 4.4 kℓ∙d⁻¹·ha⁻¹ and 8.7 kℓ∙d⁻¹·ha⁻¹. The average
demand was 10.4 kℓ∙d⁻¹·ha⁻¹ for calculation based on the residential area. The results are useful when crude estimates of AADD are required for planning new land developments.

Keywords: urban water demand, suburb area, residential