Using biological indicators to characterize the natural flow regime in wadi zomar stream/ Palestine

Abstract

The Zomar stream has been suffering for over 50 years from a variety of domestic, agricultural and industrial pollution sources together with development pressures in the open spaces that surround the stream. The aim of this study was to assess the physicochemical and microbiological quality of the Wadi Zomar through one-year long monitoring in West Bank, Palestine in order to assess the key factors and variables that play role in the environmental flow regime of the stream. In the base flow conditions, the amount of pollutant load varied temporally according to the amount of load from point sources along the Wadi and spatially with distance from the same sources. Significant variation was observed in response to the hydrological behavior of the catchment. The data shows that commonly the bacterial community in the Wadi is affected by two factors; the first is the cumulative factor from the beginning of the winter season, where the bacterial potential to re-enhancing its growth is limited with more rain events along the hydrological year. The second is flow event dilution where the maximum bacterial removal was noticed at the maximum flood within one flow event. Higher flows and more frequent washout of bacteria led to lower bacterial concentrations. Average total Coliform levels in Zomar stream were 7x1016, 4x 10', 8x10'6 cfu/100 mL all over the year. During discharge event this average reduced to 7x10'4, 4x 107, lx1014 cfu/100 mL showing log removal of 2, 9 and 2.9 for all three sites, Deir Sharaf, Anbta and Tulkarem, respectively. In case of FC, average concentration were 4x1013, 6x1012, 2x 1011 cfu/100 mL and reduced to 5x109, 4x105, 2x101° cfu/100 mL showing log removal of 3.9,7.2,1.