Water flows into Acton from rain and groundwater, and from a few small streams that flow into Acton. Water flows out of Acton through groundwater and surface water (primarily, the Assabet River). Water cycles through Acton from rain and streams to stormwater systems, to groundwater, up through wells and plumbing systems to lawns and wastewater treatment systems, and eventually back into groundwater or surface water.
All of these places, processes, and transitions create challenges in ensuring that people and other life in Acton have enough clean water to thrive.
We sit on an ocean of water in the various rocky and sandy areas underground, but bringing that water up sustainably and safely has two main risks:
- Quantities are limited by the need to pump from areas that can provide enough flow. Our public water supply, in particular, fills tanks that supply thousands of Acton homes. During periods of heavy use, the pumping can’t keep up, the tanks start to drain, and the Acton Water District needs to call for various water-use restrictions. The most intensive use is watering lawns.
- The quality of our water is threatened by plumes of contaminants. Two exceptionally large and important sources of contaminants are our local Superfund sites, WR Grace and NMI (Nuclear Metals, Inc.).
We haven’t relied on surface water for drinking water, but Nagog Pond is used as a drinking water source by neighboring Concord.
After water is used by Acton households and businesses, it usually ends up next in one of these places:
- Lawns and gardens. Some water is taken up back into the groundwater, and some evaporates. Evaporated water enters our local atmospheric weather system, and generally escapes the town boundaries quickly.
- Local or town-wide wastewater treatment. Consider two overlapping maps: (1) where local treatment via leach fields is possible, and (2) where the Town provides sewers to carry contaminated water to the wastewater treatment facility in South Acton. These two maps strongly determine development patterns in Acton, and where further environmental impacts from residential and commercial development will happen.
Finally, water entering Acton as rain falls directly into streams or woods, where it re-enters the cycle without further contamination, or it falls on human infrastructure such as houses or roads, where it may pick up contaminants. The handling of stormwater run-off is rapidly changing, as new regulations are developed, and as climate change moves us toward different weather patterns — typically, of longer and more-severe droughts and stronger and more-intense storms.