Alum is an abbreviation for aluminum sulfate, a non-toxic chemical used to treat high phosphorus levels in lakes. Alum binds with loose phosphorus in the water and settles to the bottom of the lake. This helps reduce harmful algae blooms, improve water clarity, and enhance habitat for fish and aquatic plants.
Source – WI DNR | Source – NALMS


NOAA Atlas 14 is a project of the National Weather Service’s Hydrometeorological Design Studies Center (HDSC) that provides precipitation frequency information for the U.S. states and territories. NOAA precipitation frequency estimates serve as the de-facto standards for designing, building, and operating infrastructure to withstand the forces of heavy precipitation and floods.

BMP/ Best Management Practices

Best management practices, or BMPs, are methods used to reduce pollution, often by reducing stormwater runoff volume and contamination. Some examples of BMPs include filtration basins and rain gardens, smart salting, reducing fertilizer use, street sweeping, and maintaining shoreline vegetation to prevent soil erosion and filter runoff.
Source – NCFSSource – MPCA


A buffer, or buffer zone, is an area of land that surrounds and protects a natural resource like a wetland, river, or wildlife habitat area. For example, a lake shoreline planted with native species can help prevent erosion and filter pollutants from runoff before reaching the lake.
Source – TNC

Clean Water Act

The Clean Water Act is a federal law that regulates pollutant discharge and sets water quality standards for surface waters.
Source – EPA


Conservation, or environmental conservation, refers to the protection, preservation, or sustainable use of natural resources such as wetlands, lakes, birds, trees, or entire ecosystems.
Source – National Geographic

Conveyance Systems

A conveyance system, or stormwater conveyance system, is a natural or constructed drainage system that moves stormwater runoff from one location to another and helps prevent water pollution. Examples include street gutters, underground storm drains, naturally occurring streams, and bioswales.
Source – LawInsider.comSource – MPCA


A culvert is a tunnel that allows flowing water, like a river or drainage ditch, to pass under roadways and other infrastructure.
Source –

Dead Zone

A dead zone is an area in a body of water with very low oxygen levels that cannot support aquatic wildlife. These areas occur due to the process of eutrophication.
Source – EPA

DO/Dissolved Oxygen

Dissolved oxygen refers to the amount of oxygen present in a body of water, and is one of the factors used to measure water quality. Fish and other aquatic creatures require dissolved oxygen to breathe, so low levels can be harmful to wildlife.
Source – EPA

Ecological Restoration/Ecosystem Restoration

Ecological restoration is the process of assisting the recovery of an ecosystem that has been degraded, damaged, or destroyed.
Source – SER


An ecosystem is a geographic area where living organisms (plants, animals, microbes, etc.) and their physical environment (soil, weather, water, etc.) interact to create specific environmental conditions.
Source – National Geographic


Eutrophication is a process that occurs in bodies of water that are polluted with excess nutrients like nitrogen and phosphorus. The high nutrient levels in eutrophic waters often lead to poor water clarity and algal blooms, which prevent sunlight from reaching aquatic plants. Without sunlight, these plants cannot produce oxygen that aquatic animals need to live. Algae also uses up oxygen as it decomposes. If enough oxygen is used up, it can create a dead zone.
Source – NOAASource – EPA


Floodplains are the flat or gradually sloping areas of land surrounding rivers and streams. They form as rivers deposit rocks and other sediments on their banks and are typically the first areas to flood during large storm events.
Source – National Geographic


Groundwater is the water underground that fills the spaces not occupied by soil, rocks, and other materials. Groundwater is a major source of drinking water, but it can only be replenished by infiltration of rain and snowmelt, so groundwater supplies can temporarily run out if too much is used at once.
Source –

HABs/Harmful Algae Blooms

A harmful algae bloom, or HAB, is an algae bloom typically caused by blue-green algae or cyanobacteria. Certain types of cyanobacteria produce chemicals that can be toxic to humans and wildlife when touched, inhaled, or consumed. HABs frequently occur in bodies of water that have elevated nutrient levels, typically caused by polluted stormwater runoff.
Source – EPA


Hydrology is the science of water and how it interacts with the environment. Hydrology explores water’s physical and chemical properties, how water is distributed across a landscape, and how water moves through the environment. The principles of hydrology help scientists and other professionals with complex tasks like planning for floods, supplying drinking water to towns and cities, and monitoring and improving water quality.
Source – USGS

Impaired Waters

Impaired waters are bodies of water, like a lake or stream, that do not meet specific quality standards due to pollution or other environmental stressors. For example, a lake might be listed as an impaired waterbody because it is unsafe for humans to swim in due to HABs/harmful algae blooms.
Source – MPCA

Impervious Surface

An impervious surface refers to any hard ground surface that prevents water from infiltrating into the soil and increases surface runoff. Examples include paved roads, roofs, parking lots, sidewalks, and soil that is compacted due to human activities.
Source – MPCA


Infiltration is the flow of water from the ground surface into the ground subsurface.
Source – MPCA

Invasive Species

An invasive species is any species of plant or animal that is: 1) non-native to the ecosystem in which it is found, and 2) is likely to cause harm to human health, the environment, or the economy.
Source – USDASource – NPS

Municipal Separate Storm Sewer System/MS4

A municipal separate storm sewer system, or MS4, is a conveyance system run by a government unit that is in charge of disposal of sewage, stormwater, or other liquid waste. MS4s must develop SWPPPs that outline specific goals and BMPs for disposal.
Source – MPCA

Native Species

A native species is any plant or animal that has lived in, developed alongside, and adapted to a certain habitat or environment for hundreds or even thousands of years. In the United States, a species is considered native only if it was found in this country before European settlement.
Source – USDA

Non-native Species

Non-native species are species of plants and animals that live in certain habitats or environments that they did not live in historically. These species are often introduced to areas outside of their native habitats by human activities. While not all non-native species are invasive, all invasive species are non-native.
Source – NPS

Nutrient Loading

Nutrient loading refers to the amount of nutrients entering a system, typically a body of water. Nutrients like phosphorus and nitrogen occur naturally in the environment but can have negative impacts on water resources when present at high levels.
Source – Vallero (2010)

Rain Garden

A rain garden is a landscaping feature – typically a shallow basin filled with plantings of native species. These depressed areas collect stormwater runoff from nearby impervious surfaces and promote infiltration.
Source – MPCASource – EPA

Stormwater Runoff

Stormwater runoff is water generated by rain or snowmelt that does not soak into the ground, but instead flows across the land surface. When stormwater runoff flows over impervious surfaces, like paved roadways or heavily compacted soils, it picks up pollutants which eventually end up in rivers or lakes.
Source – EPA


A subwatershed is a smaller watershed within a larger watershed. For example, the Mississippi River’s watershed covers 15% of the land in North America. Before all of that water, from Minnesota, Montana, Pennsylvania, Louisiana, and beyond, drains into the Mississippi River, it first drains into a series of smaller rivers and lakes. These smaller bodies of water, and the areas that drain into them, make up subwatersheds.
Source – EPA


A swale is a type of conveyance system – typically a long, linear, vegetated ditch used to direct stormwater runoff, promote infiltration, and improve water quality. Swales are commonly seen running alongside roadways.
Source – NCSU ExtensionSource – MPCA

SWPPP/Stormwater Pollution Prevention Plan

A stormwater pollution prevention plan, or SWPPP, is a site-specific, written plan, typically required by construction permits to comply with the Clean Water Act. SWPPPs outline and describe the BMPs that construction site operators will use to prevent stormwater contamination and control sedimentation and erosion.
Source – EPA

TMDL/Total Maximum Daily Load

Total Maximum Daily Load, or TMDL, is the maximum amount of a pollutant that can enter a body of water without surpassing EPA water quality standards. If the pollutant levels in a body of water exceed the TMDL, it is classified as an impaired waterbody.
Source – MPCASource – EPA

TP/Total Phosphorus

Phosphorus is a nutrient that occurs naturally in the environment in many different forms. Total phosphorus, or TP, refers to the combined quantity of all types of phosphorus found in a system. Elevated TP levels in waterbodies, typically caused by nutrient pollution in stormwater runoff, can cause problems with water quality, including eutrophication, low levels of dissolved oxygen, and HABs.
Source – EPA


Turbidity is a measure of water clarity, or how clear water is. Turbid waters, or waters with high turbidity, are cloudy or murky because they contain particulate matter like soil, algae, or other sediments. Some bodies of water are naturally turbid, but high turbidity is often a sign of poor water quality.
Source – USGSSource – MPCA

Water Clarity

Water clarity is a measure of how far down sunlight can travel into a body of water. When water clarity is high, sunlight reaches deeper into lakes, supporting growth of aquatic plants that create habitat for fish and other wildlife. Water clarity is often negatively impacted by stormwater runoff that contains sediments and high nutrient levels.
Source – EPA

Water Quality

Water quality is a measure of how healthy a body of water is. A lake or stream’s water quality is impacted by several factors, including nutrient and suspended sediment levels, dissolved oxygen concentrations, and the presence of pollutants, harmful algae, or bacteria.
Source – NOAA


A watershed is an area of land in which all flowing water is channeled to a central location, like a lake, river, reservoir, or ocean.
Source – NOAASource – MPCA

Watershed District

A watershed district is type of local government unit, established by the Minnesota Watershed District Act of 1955. Watershed districts manage local water resources based on the geographic boundaries of their watershed, rather than political boundaries. Because watershed boundaries often overlap political boundaries, watershed districts frequently work alongside city or county government units to manage their shared water resources.
Source –


A weir is a small dam-like structure built across a river or stream that alters the natural flow of water without stopping its flow altogether. Weirs can be used to raise or lower water levels, alter water flow patterns, or measure the rate of water flow.
Source – University of Calgary


A wetland is an area of land where the soil is covered by water or where water is present very close to the soil surface. Wetlands can be temporary, seasonal, or permanent and are largely characterized by their underlying hydrology.
Source – EPA