Stormwater

Stormwater is water that comes from precipitation. It either soaks into exposed soil, makes it way to streams and rivers or remains on top of impervious surfaces, like pavement or rooftops. 

Water that falls onto pervious surfaces is absorbed into the ground to the extent the ground - which acts like a sponge - can sponge it up. Water that cannot be absorbed - think of a kitchen sponge that is fully saturated - sits on the surface and forms a pond. 

Water that does not pond travels downhill. Whatever "gunk" is on hard surfaces will get picked up by, and travel with, the water, and will either go into the soil elsewhere or into stormwater pipes that eventually carry the water, and all the "gunk" with it, to streams and other bodies of water where the pollutants can cause problems.    

The dirtier the water in the stormwater system, the more polluted its final resting place. There can also be a point where these very streams and rivers simply can’t handle any more water. When this happens, these waterways overflow. 

The new development code will seek to manage this effectively.

Ultimately, when any development is approved, the City will collect more stormwater. That either means installing or upgrading necessary - and costly - infrastructure.

Greenville residents should keep two things in mind.

First, stormwater will mix with chemicals and heavy metals collected at commercial and industrial sites, along with "gunk" from construction areas, roads and parking lots. The amount and toxicity can be mitigated on the front end, either by a change in resident and business property owner behavior - like curbing the use of lawn fertilizers - or on the back end by more expensive treatment of the collected stormwater.  

Second, stormwater is often a volume problem to solve. Water from rain still must go somewhere, and that requires costly infrastructure to collect and convey the water from driveways, parking lots and roads into a series of drains and pipes that ultimately discharge untreated stormwater into a local water body like the Reedy River.

Population growth and development are major contributors to the amount of pollutants in the runoff as well as the volume and rate of runoff from impervious surfaces. Because a building block of GVL2040 is that there was uniform agreement in Greenville that the city should continue to grow, and grow robustly. The City will continue to develop and develop robustly. More pollutants and more water volume are going to result. Because there will be fewer and fewer acres of natural, undeveloped land to absorb rainwater, and more driveways, roads, sidewalks and rooftops channeling more unabsorbed water into smaller and smaller sponges, every zoning decision becomes, in effect, a stormwater management problem to get ahead of.

As a City, Greenville strives to:

• Inasmuch as possible, prevent harm due to periodic flooding, including loss of life and property and threats and inconveniences to public health, safety, welfare, and the environment.
• Ensure that development does not increase flood and drainage hazards to others, or create unstable conditions susceptible to erosion.
• To the greatest possible, limit the financial burden on the taxpayer for flood control projects, repairs to flood-damaged public facilities and utilities, and for flood rescue and relief operations.
• Protect, conserve and promote orderly development while protecting and conserving the land and water resources.
• Protect buildings and improvements to buildings from flood damage to the greatest extent possible.
• Conserve the hydrologic, hydraulic, water quality and other beneficial functions of floodprone areas and regulatory floodplains.

To achieve these goals, the City manages and regulates stormwater runoff and sediment and maintains a system of stormwater management facilities.

The key tool at the City of Greenville’s disposal for the management of stormwater the mandate to determine the amount of impervious area allowed on a developed property. This is the single most important part of stormwater management.

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