ABSTRACT
Water quantity as well as water quality issues must be addressed during a drought and especially after a drought period ends. One common event that can occur during and following a drought is a bloom of algae and/or cyanobacteria, the latter of which can release foul-tasting and odorous substances into waters and can produce harmful toxins. Point source pollution is not diluted as well during a drought period as in nondrought periods. Nonpoint sources of pollution such as manure or vegetation that dies during a drought can run off into watercourses and eventually enter lakes and reservoirs once normal rainfall resumes. Dissolved organic matter (DOM) reacts with the chlorine disinfection agent producing disinfection by-products (DBPs) such as trihalomethanes (THMs), known to be carcinogens. Once identified, water quality issues will have to be dealt with by the water supply manager, but technologies are available if time is taken to prepare for problems that may have occurred during past droughts or that may be anticipated during a current drought. For potable water supply, the manager of operations will have to monitor for these chemicals and adjust chlorine levels to keep THMs below regulatory maxima and still provide for drinking water safety by disinfecting suspected pathogens. Well-developed commercial technologies that can address water quality problems that emerge during a drought and once a drought is broken are available. Water supply operation managers must keep vigilant to quickly identify water quality problems that are unique to drought events and take measures to prevent or at least minimize any detrimental short- and long-term effects that result from the drought. Climate change may alter the frequency and severity of droughts, requiring water managers to act more forcefully to acquire technologies that will help solve water quality problems that droughts bring along with them.
