Stormwater

The stormwater department of the Hobart Sanitary and Stormwater District manages Hobart’s storm sewer system which consists of catch basins, inlets, and conveyance pipes that collect and transfer stormwater from rainfall and snow melt from streets, yards, buildings, and parking lots and then release it to local streams and rivers. The City is responsible for managing stormwater and implementing a program to reduce pollution in stormwater runoff and improve water quality. 

What is Stormwater Runoff?

Stormwater runoff is part of the natural hydrologic process and occurs when rainwater that does not infiltrate into the ground flows into water bodies such as creeks, lakes, streams, or rivers. In suburban areas, the stormwater runoff often has the benefit of passing through naturally vegetated areas, which slows down the velocity of the water and ultimately filters it for pollutants and sediments. In urban settings, however, natural vegetation and topography have frequently been altered to prevent stormwater from naturally soaking into the ground and so it is most often carried by storm drains. 

When the drainage pattern of a watershed is altered with the addition of impervious surfaces such as driveways, parking lots, and buildings, flows increase in concentration and velocity and pick up sediments and pollutants from land surfaces at an increased rate. Stormwater that flows through urbanized areas to receiving waters is called "urban stormwater runoff." 

The City of Hobart has developed a stormwater program that manages the pollutants and impacts from urban stormwater runoff. The program includes education, stormwater quality and quantity measures, and a stormwater utility.

Screenshot 2024-07-19 104738

Pollutants

Urban runoff is known to carry a wide range of pollutants including:

  • Heavy metals
  • Nutrients
  • Pathogens
  • Petroleum hydrocarbons
  • Sediments
  • Synthetic organics such as pesticides
  • Trash and debris

Once pollution reaches water bodies, it can harm aquatic life, damage ecosystems, and even end up in water used for drinking or recreation. Protecting our water bodies from all sources of contamination can be accomplished through the cooperation of citizens, government, and businesses.

Community Impacts

Because urban runoff does not originate from a distinct "point" source (e.g., an industrial discharge pipe), it is also often referred to as nonpoint source pollution. These pollutants in urban runoff could negatively impact the vitality of our municipality on many levels.

Urban runoff can:

  • Alter the physical, chemical, and biological characteristics of water bodies to the detriment of aquatic and terrestrial organisms
  • Make beaches and rivers unsightly or unsafe for human contact
  • Negatively impact beneficial activities and users including water recreation, commercial fishing, tourism and aquatic habitat

In some cases, pollutants of concern may not even be visible to the naked eye.