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How does construction affect runoff?

How does construction affect runoff?

Runoff flows over construction sites, picking up sediment and other pollutants such as building materials, concrete washout, paint, fuel, wastewater, oil and solvents. The contaminated runoff then enters the storm water system and is discharged into local streams, rivers and lakes.

What affects the rate of runoff?

Watershed factors affecting runoff are land slope, shape, soil, and land use. The principal effect of land slope is on the rate of runoff. Runoff will flow faster on a steeper slope.

What causes increased runoff?

Impervious surfaces, or surfaces that can’t absorb water, increase runoff. Roads, sidewalks, and parking lots are impervious surfaces. Materials as diverse as car-washing soaps, litter, and spilled gas from a gas station all become runoff. Runoff is a major source of water pollution.

How can we prevent runoff pollution?

You can do a lot to help minimize stormwater problems

  1. Maintain your car or truck.
  2. Wash your car at a commercial car wash rather than in the street or in your driveway.
  3. Drive less.
  4. Cut down on fertilizers, pesticides and herbicides.
  5. Remove part or all of your lawn.
  6. If you are on a septic system, maintain the system.

How do you stop silt from running off?

The best solution is to retain as much sediment as possible before it reaches paved surfaces. Install a silt fence at the inlet side of a storm sewer or culvert, rather than at the discharge where there is greater velocity and less storage area.

What are control measures for stormwater runoff?

Stormwater control measures refer to what is defined by EPA (1999) as “a technique, measure, or structural control that is used for a given set of conditions to manage the quantity and improve the quality of stormwater runoff in the most cost-effective manner.” SCMs are designed to mitigate the changes to both the …

How do you reduce surface runoff?

What can you do to reduce the runoff from your property?

  1. Disconnect/Redirect Downspouts.
  2. Use a rain barrel to capture rain from your roof.
  3. Plant a rain garden.
  4. Plant trees.
  5. Reduce impervious surfaces; install permeable pavement.
  6. Plant a green roof.

What are the elements of runoff?


  • Direct rainfall over the stream:-
  • Surface runoff or overland flow: –
  • Subsurface flow or interflow:–
  • Base flow, groundwater flow or Dry weather flow:-

How do you control surface runoff?


  1. Mulch Farming.
  2. Soil Conditioners.
  3. Cover Crops.
  4. Alley Cropping.
  5. No-tillage Farming.
  6. Ploughing.
  7. Strip Cropping.
  8. Contour Farming.

How are physical and Human Factors affecting runoff?

A variety of physical & human factors affect runoff (the flow of water over the Earth’s surface). These are summarised below. In temperate climates, where seasonal change is evident, runoff levels can vary greatly throughout the year.

How does rainfall affect the volume of runoff?

Rainfall intensity influences both the rate and the volume of runoff. An intense storm exceeds the infiltration capacity by a greater margin than does a gentle rain. Thus, the total volume of runoff is greater for the intense storm even though the total precipitation for the two rains is the same.

How does urban development affect the amount of runoff?

Runoff and Urban Development. Urban development can greatly increase the amount of precipitation that is converted to runoff in a drainage basin. Most paved surfaces and rooftops allow no water to infiltrate, but instead divert water directly to storm channels and drains.

What are the main causes of surface runoff?

1 Surface runoff is precipitation runoff over the landscape. Impervious areas cause excessive runoff. 2 Human activities can affect runoff. Severe erosion can occur when people manipulate the landscape without regard to how flowing rainfall runoff will erode exposed soil. 3 Urban development and flooding.