If you’ve ever owned or managed a piece of land, you’ve likely had to deal with runoff, even if you didn’t know it. Managing runoff can be a crucial component of maintaining the health of your job site or managed land. But before you get into the ins and outs of dredging to control runoff water, it’s important to understand what runoff is, where it comes from and how you can best manage it.
Where Does Runoff Typically Occur?
Knowing what runoff is plays a big role in learning where it’s typically found. Runoff is any water that runs off the land’s surface. It’s a large component of the water cycle, and when rain pours, the streets flood this runoff into the sewer drains. That’s one example of how we manage runoff — but more on that later.
When rain meets land that is over-saturated because of impervious surfaces, the water will run overland. The laws of nature prove that water always flows toward the path of least resistance and, like all other things, follows the pull of gravity. Because of this, runoff flows downward until it meets a large body of water, such as a river, creek, ocean or reservoir.
The flow of runoff is largely impacted by the land’s physical characteristics and the weather’s meteorological factors.
Meteorological factors that influence storm water runoff management include:
- The type of precipitation and its intensity, amount and duration
- The distribution of rainfall over the drainage basin
- The direction of storm movement
- Previous precipitation or previous soil saturation
Physical traits of the land that impact runoff can include:
- Land use
- Soil type
- Drainage area
- Basin shape
- Ponds, lakes, reservoirs and sinks in the basin
Why Does Runoff Occur?
Knowing where runoff occurs, we can follow the water uphill to its source to see where it comes from. You may wonder, isn’t it all from rain? The answer is yes — but also no. Rain is the most common cause for runoff, but we might also see other causes for it, especially when managing an industrial plot of land.
Depending on where your land sits in relation to any nearby mountains, snowmelt is the most common form of runoff. Snowmelt occurs when warm temperatures cause heavy snow on the mountains to melt on surfaces that can’t absorb the water, thus causing the snowy water to run off the mountain toward a nearby body of water.
Additionally, whether intentional or not, managing a piece of land for any number of reasons (even non-industrial) can cause man-made runoff. This type of water is referred to as point source and nonpoint source pollution.
Dredging is a common practice used to reduce the effects of both forms of runoff.
Point Source Pollution
This direct form of runoff is caused by the emptying of water directly into a body of water. This could be factory runoff being sent directly into a creek or river. However, places as common as a residential home could also be a contributing factor for point source pollution.
Section 502(14) of the Clean Water Act defines “point source” as any discernible, confined and discrete conveyance from which pollutants are discharged. These conveyances can include any:
- Discrete fissure
- Rolling stock
- Concentrated animal feeding operation
- Floating craft or other vessel
Despite its name, point source pollution doesn’t always carry excessive negative impacts on local environments and ecosystems. In most areas, legislation exists at the regional, state and national levels to indicate the type and amount of runoff that industries are allowed to release into the environment.
Nonpoint Source Pollution
This form of runoff is the catch-all for all runoff that doesn’t meet the above definition for point source pollution. It can apply to any water that doesn’t directly travel into a waterway. Nonpoint source pollution can be found in urban, suburban and rural areas alike.
While this type may in theory seem less harmful than its more direct form, it can actually be more damaging to local ecosystems. Runoff water can travel overland, bringing with it the harmful chemicals and pollutants it encounters.
Farmlands are the most common contributors to nonpoint source pollution, as the frequently used fertilizers and pesticides get swept up in the runoff.
Whenever impervious surfaces are present, the amount of runoff increases and thus allows for more pollutants to be carried off. More local examples of runoff pollutants include car-washing soaps, litter and spilled gasoline.
Ways to Manage Runoff Water With Dredging
If you are operating on a work site, you will likely be exposed to runoff water, which may be damaging to your local ecosystem and the health of the site or your managed land. Dredging is often used to manage the effects of runoff, especially in and around job sites. Dredging is the process of removing unwanted sediment below the surface of the water with a vacuum pump and other mechanical tools.
In addition to runoff management, people use dredging for:
- Deepening a water basin, allowing boats and ships to pass
- Obtaining aggregates for concrete manufacturing
- Obtaining materials for civil engineering projects
- Excavating trenches for pipelines, cables and other projects
- Increasing channel capacity and flood prevention
- Preventing the spread of contaminants to other areas of the water body
- Reclaiming land
When managing the materials created by dredging projects, handling is best done at upland sites with materials spread out, seeded, mulched and stabilized.
In locations where stormwater is leaving the dredging project or managed areas, temporary sediment basins are largely recommended when possible. They contribute to the collection of point source and nonpoint source pollutants.
Additional best practices for controlling runoff with dredging equipment include:
- Diverting stormwater away from exposed or disturbed site areas
- Planning the use and movement of designated equipment to minimize soil disturbance
- Stabilizing drainage ways
- Expediting re-vegetation of sites and minimizing clearing of vegetation
- Identifying and protecting existing areas of heavy vegetation, such as trees
- Inspecting surface waters including drainage ditches and conveyance systems for evidence of sediment being deposited from erosion
The Dino 6/Dino 8 Dredge
Whether you work for a homeowners association, golf course, pond and lake management association or other industry, you’ll need a strong dredger to keep your water bodies clean. The Dino 6 Dredge is a hard-hitting, small dredging machine with durability that competes with heavier and more expensive machinery. This easy-to-operate machine comes with a 6-inch pump and 66-inch wide cutterhead to get into hard-to-reach dredging areas.
This portable machine is powered by a 4-cylinder Cummins diesel engine rated at 65 horsepower. Check out the Dino 6 brochure for more information.
For those who need more power, the Dino 8 doubles the performance output of the already powerful Dino 6. This dredge utilizes a JCB engine for maximum power output. The submersible pump measures 8 inches and is designed to work efficiently in materials such as sod and cobble.
How GeoForm International Can Help Dredges and Rentals
GeoForm International is an expert in environmental machinery, site upkeep and runoff management. To get the best performance on your job site, managing runoff and sedimentation dredging will be an essential part of your operations — and we can help you with the job.