Climate Change and Water Quality


Climate change significantly (and often negatively) impacts the water cycle. Unusual changes in weather patterns directly affect the amount and quality of available water. 

  • Flooding: Increased water flows & precipitation leads to increased runoff, which increases the amount of industrial and agricultural pollutants from land activities that end up in source water. Much of this increased pollution is not treated by local water treatment facilities, and passes through to the end users’ taps. Aquagenuity’s system is designed to aggregate and report this data at the tap.
  • Drought: Water scarcity interrupts water flow patterns and decreases the amount of freshwater available to replenish and purify the water resources that are essential to human health and well-being. This leads to a state known as water stress, when the local water ecosystem is unable to naturally dispel discharges from industry, agriculture, and human waste. Aquagenuity’s data can create maps to help track the ways in which drought-stricken areas are experiencing these correlated impacts.
  • While the strain on the water cycle increases due to climate change, the pollution from industrialization is also on the rise. According to the World Health Organization: “The absolute quantity and the diversity of pollutants reaching freshwater systems have increased since the 1970s. These include not only biological contaminants, e.g. microorganisms responsible for traditional water-borne diseases, but also heavy metals and synthetic chemicals, including fertilizers and pesticides (1). Depending on the type of contaminant and degree of exposure, acute or chronic health impacts may result, along with impacts on the environment.”
  • Click for a Visual Summary of the Impacts of Climate Change on Water Supply
  • Click for Academic Summary of Weather- and Climate-Related Impacts on Water by U.S. Region
  • Click for a Brief Overview of Climate Change’s Impact on the Water Cycle

The Aquagenuity platform is designed to provide real-time data and visualizations of climate-related impacts on water quality, providing unprecedented insights into hyperlocal water quality as it changes due to flooding, drought, and other outcomes of climate change.

Below find the full text article from the Union of Concerned Scientists for Reference:

Water in its various forms is always on the move, in a complex process known as the water cycle. Global warming is already having a measurable effect on this cycle, altering the amount, distribution, timing, and quality of available water. Water users – from communities, to industries, to ecosystems – are in turn affected: their activities and functions depend, either directly or indirectly, on water. 

Change is underway: With climate change, the water cycle is expected to undergo significant change. For example, a warmer climate causes more water to evaporate from both land and oceans; in turn, a warmer atmosphere can hold more water – roughly four percent more water for every 1ºF rise in temperature. Changes like this are expected to lead to specific, and in many cases negative, consequences. Some parts of the U.S. – in particular, the Northeast and Midwest – can expect increased precipitation and runoff, especially in winter and spring, leading to increased flooding.  Other areas – notably the Southwest – can expect less precipitation, especially in the warm months, and longer, more severe droughts as storm tracks shift northward leaving arid areas increasingly dry.

Rain versus snow can make a critical difference

The form that precipitation takes is also subject to change in response to warming: climate projections for many regions of North America suggest less snow, overall, and more rain.  In areas dependent on the gradual melting of snowpack to supply surface water through the warm months, this means lower flows and greater water stress in summer – a trend already in evidence in parts of the western U.S.  While the effects of climate change on groundwater are not fully understood, rising water competition and stress at the surface are likely to drive greater use – and overuse – of this resource.

Overall, wet areas are expected to become wetter and dry areas drier, placing additional stress on the nation’s over-taxed water systems as well as water-dependent sectors.

Water quality affects people and ecosystems

Declining water quality is another consequence of climate change. Water temperature, for example, will generally rise in streams, lakes, and reservoirs as air temperature rises. This tends to lead to lower levels of dissolved oxygen in water, hence more stress on the fish, insects, crustaceans and other aquatic animals that rely on oxygen. As more – and more intense – precipitation leads to increased runoff in certain regions, we can also expect more pollution to be washed into our waterways: sediments, nitrogen from agriculture, disease pathogens, pesticides, and herbicides.  Naturally, the pollution load in streams and rivers will tend to be carried to larger bodies of water downstream – lakes, estuaries, and the coastal ocean – where one of the more dramatic consequences of heavy runoff can be blooms of harmful algae and bacteria. 

The tide is rising 

One of the starkest effects of climate change is the anticipated rise in sea level worldwide. This occurs for two main reasons – the expansion of the ocean as it warms, and the increased melt from ice sheets, ice caps and glaciers. Along with alarming threats to coastal communities, infrastructure, economies and ecosystems, this rise has implications for available freshwater, as rising sea levels drive saltwater into freshwater aquifers. To be useful for drinking or irrigating, more water from our aquifers, then, would need to be treated, usually by energy-intensive processes. Given the wide range of human activities that depend – directly or indirectly – on water, future climate-driven changes in water resources will affect many aspects of our lives.



A great summary from the EPA:

“In many areas, climate change is likely to increase water demand while shrinking water supplies. This shifting balance would challenge water managers to simultaneously meet the needs of growing communities, sensitive ecosystems, farmers, ranchers, energy producers, and manufacturers.


In some areas, water shortages will be less of a problem than increases in runoff, flooding, or sea level rise. These effects can reduce the quality of water and can damage the infrastructure that we use to transport and deliver water.”

An explanation of how heavy precipitation events impact water quality:

“Water quality could suffer in areas experiencing increases in rainfall. For example, in the Northeast and Midwest increases in heavy precipitation events could cause problems for the water infrastructure, as sewer systems and water treatment plants are overwhelmed by the increased volumes of water.[1] Heavy downpours can increase the amount of runoff into rivers and lakes, washing sediment, nutrients, pollutants, trash, animal waste, and other materials into water supplies, making them unusable, unsafe, or in need of water treatment.”

A Call to Make the Link Between Climate Change and Water Quality from the United Nations:

Typically, policy discussions and scientific studies today omit the important linkages between water quality and climate change, whereas the impacts of climate change on the quality of freshwater systems are likely to be significant. It is evident in our planet weather and climate patterns are changing and will continue to shift, which may increase in return the occurrence of extreme weather conditions and modify the normal balance of water bodies and ecosystems, leading to the degradation of water quality. These changes in water quality not only affect the economic and social welfare but also the sustainability of vital environmental flows, ecosystems and biodiversity. More scientific understanding is hence needed to address the physical, chemical, biological and socio-economic impacts that current and expected climate change have, and will continue to have, on the quality of the world’s freshwater resources. Furthermore, international initiatives and national strategies are equally important to promote necessary policy responses to this pressing water quality challenge, particularly for the attainment of the 2030 Agenda and SDGs.”

Summary from Center for Climate and Energy Solutions:

“Excessive precipitation can also degrade water quality, harming human health and ecosystems. Stormwater runoff, which often includes pollutants like heavy metals, pesticides, nitrogen, and phosphorus, can end up in lakes, streams, and bays, damaging aquatic ecosystems and lowering water quality for human uses.

Many cities in the United States use a combined sewer system, where both stormwater and wastewater are mixed, treated, and released. Heavy rainfall [flooding, hurricanes, etc] can overwhelm such systems, sending excess stormwater, wastewater, and untreated sewage directly into the environment, risking public health and disrupting local fisheries.”

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