Stormwater Dashboard




Definitions of Common Terms

  • BMP – Best Management Practice that are structural, vegetative, or managerial practices used to treat, prevent, or reduce water pollution
  • Brook – a small stream
  • Catch Basins – a curbside opening that collects rainwater from streets and serves as an entry point to the storm drain system.
  • Culverts - a tunnel or pipe carrying a stream or open drain under a road or railroad
  • Dam - a barrier constructed to hold back water and raise its level, forming a reservoir sometimes used to generate electricity or as a water supply
  • Detention vs Retention Basins - Detention and retention both refer to storing rainwater on-site during a storm event, when the risk of flooding is highest. The difference is that when water is detained, it is slowly released into a stream or river and leaves the site. When water is retained, it is not intended to leave the site.
  • Dry Well - a shaft or chamber constructed in the ground in order to aid drainage, sometimes containing pumping equipment
  • French Drains - a simple trench dug in the ground in the most problematic areas of the yard. The trench is filled with a perforated pipe wrapped in water-permeable fabric, and the pipe is covered with several layers of stone or gravel.
  • Generators/Battery Backup - a back-up electrical system that operates automatically.
  • Groundwater - water underground in saturated zones beneath the land surface
  • Intermittent streams - A stream that has flowing water during certain times of the year, when groundwater provides water for stream flow. During dry periods, intermittent streams may not have flowing water. Runoff from precipitation is a supplemental source of water for stream flow.
  • Infiltration Systems - components that are used to capture surface water runoff and allow it to infiltrate (soak) and filter through to the subsoil layer, before returning it to the water table below
  • Outfalls – the place where a river, drain, or sewer empties into the sea, a river, or a lake
  • Rain Gardens - a garden that lies below the level of its surroundings, designed to absorb rainwater that runs off of a surface such as a patio or roof
  • Reservoir Pond - an artificial lake where water is stored.
  • Resource Area- An area or location that falls under Conservation Commission Jurisdiction
  • Riprap - a permanent layer of large, angular stone, cobbles, or boulders typically used to armor, stabilize, and protect the soil surface against erosion and scour in areas of concentrated flow or wave energy.
  • Run-off - rain and melting snow that flows off building rooftops, driveways, lawns, streets, parking lots, construction sites, and industrial storage yards. 
  • Sewer vs. Storm drain - A storm drain carries storm water and is not treated; it goes directly to water body, pollutants, and all. A sanitary sewer carries domestic waste and goes to the wastewater treatment plant where the water goes through a complicated process where it is cleaned and released back into the water.
  • Stormwater water that originates from precipitation (storm), including heavy rain and meltwater from hail and snow.
  • Sump - a pit or hollow in which liquid collects, especially one in the floor of a mine or basement
  • Sump Pump - a device that moves water from your basement to the outside of your home.
  • Surcharging - the condition in which an entire storm drainpipe section is submerged, and the pipe is flowing full under pressure.
  • Vernal pools - shallow depressions that usually contain water for only part of the year. They are often associated with forested wetlands.
  • Wetlands - areas where water covers the soil or is present either at or near the surface of the soil all year or for varying periods of time during the year, including during the growing season.