Managing water quality impacts from drought on drinking water supplies

Abstract

Droughts, which are difficult to predict, are a natural feature of the hydrology in most regions.Climate change, however, has the potential to increase the frequency and magnitude of future droughts. While the lack of water availability during droughts is widely publicized, there are equally severe water quality impacts that occur during and after droughts as well. Recent droughts have led to water quality implications for drinking water supplies including turbidity, taste and odor, pathogen concerns, and challenges in managing disinfection byproducts (DBPs). This paper presents the results from a series of case studies prepared for a Water Research Foundation study on the effects of extreme weather on drinking water quality in order to help utilities prepare for vulnerabilities under future climate change. A key finding from the case studies is that droughts can fundamentally alter nutrient cycling and biota within both watersheds and reservoirs that influence water quality for months or years after the event. A few of the critical management actions for responding to degraded water quality related to droughts include awareness of potential impacts, increased monitoring during and after the event, and capacity to quickly adjust treatment processes.

Performance of regional water purification plants during extreme weather events – three case studies from New South Wales, Australia

“…LGAs' preparation and response to drought are essential to resilience following periods of drought. Improving an organisation's technical knowledge, in-house expertise and capability, and learning from past events on local, national, and international levels can bene t outcomes following drought (Wright et al, 2014). Monitoring water quality levels within a system and implementing strategies to address common water quality themes associated with drought, including turbidity, taste and odour, higher chemical and physical concentrations, and pathogen concerns, will greatly assist in maintaining compliance with standard regulations.…”

Dry landscapes and parched economies: A review of how drought impacts nonagricultural socioeconomic sectors in the US Intermountain West

“…Droughts can lead to water quality implications for drinking water supplies, including turbidity, taste and color, lower dissolved oxygen levels, and the altering of nutrient cycling and biota within both watersheds and reservoirs that can influence water quality for months or years after the event (Governor's Drought Task Force, 2004; Wright et al, 2014; Yusa et al, 2015). The decreased volume of water in lakes and reservoirs increases the concentration of pollutants, such as municipal waste water and thermoelectric power plant return flows (Bates et al, 2008; Wright et al, 2014). Drought‐related wildfires can also damage water infrastructure and cause chemical and physical damage in rivers and streams, resulting in short‐term water quality issues and long‐term watershed complications (NRCS, 2016; Ranalli, 2004; Rhoades et al, 2019; Rust et al, 2018).…”

Rural Drinking Water Safety under Climate Change: The Importance of Addressing Physical, Social, and Environmental Dimensions

“…Dry spells or droughts, and extremely hot temperatures Reduced stream and river flow which raises pollution concentration. [16] Increase in growth of algae and some toxic bacteria in surface water and increase in wildfires that raise contaminant loads in surface water, which exert strain on water treatment processes (if present, such as in rural towns). [17,18] Diminished groundwater recharge, combined with over-abstraction, leading to salinization of groundwater sources.…”