construction- erosion and sediment control
Construction activities can lead to erosion- the wearing away of land through wind, water, gravity, or other processes. Not only can soil loss negatively affect the site under development, but the introduction of heightened levels of soils and sediments into local waterways can be harmful to aquatic environments and the communities that depend upon them. It’s the contractor’s responsibility to limit erosion through responsible practices.
Learning the importance and proper management strategies for sediment and erosion control not only saves you time and money, but also supports the protection of community and wildlife health. From destroyed fisheries, to impaired recreational activities, to polluted waters, sediment pollution can severely affect the health and quality of life of southeastern Wisconsin residents. You have the ability to help prevent these problems by understanding, implementing, and maintaining Best Management Practices (BMPs) for sediment and erosion control.
What is Sediment?
Sediment is the result of natural and human-induced erosion that breaks and loosens soil and rocks. Natural erosion includes physical and chemical weathering caused by rain, wind, waves and other natural phenomena. Land disturbing activities, like construction projects, can produce even larger amounts of sediment in a short period of time. Once sediment at a site is loosened, it can easily be transported away from the site through stormwater runoff and end up in our lakes and rivers. Controlling the fate of soil and sediment is the responsibility of anyone engaged in altering our landscapes. As more soil is exposed and disturbed, the potential for sediment pollution and associated damages grows.
“For every acre under construction, about a dump truck and a half of soil washes into a nearby lake or stream unless the builder uses erosion controls.” - WI Erosion Control for Home Builders
Impacts of Sediment Pollution
When sediment is picked up by stormwater, multiple problems ensue:
Clogged or blocked storm drains decrease drainage ability and increase the likelihood for localized flooding.
Accumulation of sediment in a waterway can change stream morphology (size/shape). This may affect the navigability of the stream for humans and animals and cause water levels to fluctuate.
Increased amounts of sediment suspended, or mixed into, the water in streams, rivers, and lakes can lead to:
More difficult and expensive treatment processes for drinking water;
Less sunlight reaching native aquatic plants, which negatively impacts their growth;
Negative impacts on fisheries resulting from clogged fish gills, reduced food sources, and inadequate breeding habitat;
Exacerbated algae growth that results from sediments that contain nutrients like phosphorus;
Increased water temperature from sediments absorbing sunlight and retaining heat, which also affects fisheries and algae growth.
Depending on where the construction project exists, the soil itself may be a problem. For example, land used for certain types of industrial or manufacturing activities may be contaminated with heavy metals or forever chemicals that exist in the soil and on the sediment particles. Take precautionary measures and work with regulators if you are in this situation.
These environmental impacts of sediment pollution also create a set of public health problems.
Degraded waterbodies often cannot sustain previously popular recreation activities like swimming and fishing. This is particularly burdensome to nearby neighborhoods and residential areas. Treatment processes can also become more expensive and time consuming, and can even result in water with a strange odor or taste to it. Under these circumstances, community, mental, and physical health decline.
Key Steps for Successfully Controlling Sediment and Erosion On-Site
To protect our shared water resources, storm sewer systems, and nearby properties, sediment and erosion control devices should be installed BEFORE any land disturbing activity begins. As the project progresses, seasons change, and the site transforms, the sediment and erosion control devices utilized will change to ensure the level of resource protection is adequate and appropriate for all regulations.
Remember, the reason for applying these control methods is to reduce the off-site effects of soil erosion, minimize the overall project expenses, and comply with federal, state, and local laws and regulations. With this in mind:
Always make sure you have the necessary permits and documentation before doing any construction. Remember- failure to comply with local ordinances can result in fines and could potentially halt the project in its tracks. With a fixed project budget and timeline, the need for proper installation and management of erosion control practices is essential. It does take time and effort to apply these BMPs, but it’s something that should be expected and included in the project planning phase.
Routinely inspect and maintain BMPs. BMPs capture and retain loose soil particles, or prevent them from eroding in the first place, so cleaning out the accumulated sediment in these devices allows for optimal efficiency. Make sure you know what type of soil you are working with; different soil compositions can lead to different management strategies. Exposed soil allows for erosion processes to take place, so reducing the amount of exposed soil is a key component for reducing erosion and sedimentation on and off the construction site.
Use compatible BMPs. While a suite of BMPs is often the best way to optimize erosion and sediment control, not all devices and techniques should be used together. For example, while mulching and seeding can both be used for temporary or permanent control measures, certain mulch materials like wood chips should only be used for temporary stabilization and not used with seed. However, straw mulch can be used with seed or without seed, depending on the soil characteristics and proximity to nearby waterways.
Sediment and Erosion Control Devices Examples
Here are some examples of sediment and erosion control methods. For a more in depth and comprehensive guide to sediment and erosion control BMPs, go to the Additional Resources section below!
Exposed soil quickly erodes by rain and wind, creating puddles and mucky conditions that deter construction.
Soil compaction from heavy equipment makes vegetation growth spotty and curbs community aesthetics.
If the proper BMPs are not used, storm drains can become clogged by sediments, leading to localized flooding.
Sediment pollution, oftentimes in combination with other types of pollution, can lead to dangerous algae blooms in once pristine waterbodies.
Construction Site Sediment + Erosion Control Terminology
Sediment vs. Erosion Control:
Erosion Control Measures: Directly reduce soil erosion on a disturbed/ exposed surface.
Sediment Control Measures: Contain and reduce eroded soil particles from leaving the site with stormwater.
Temporary vs. Permanent Devices
Temporary Control Devices: Used during project construction phases to stabilize soil and control sediment from going off-site. Should be eventually replaced with a permanent control device or removed when full stability has been restored.
Permanent Control Devices: Used to ensure erosion and sediment are managed after the final construction phase has ended.
The black rolls on the ground in this image are sediment control logs, also known as wattles or filter logs. Filled with materials such as straw, wood chips, or rocks, these flexible temporary sediment control devices are used to slow and filter water leaving the site. This is a well rounded BMP for ditch checks, inlet protection, and water redirection. Stake placement during installation is crucial for this device, as fast moving water can displace the log and make sediment capture more difficult. Notice the crisscross pattern along the ends of the roll to ensure proper stability on a slope.
Known as horizontal slope grading, this erosion control technique reduces soil erosion potential by creating horizontal grooves along an exposed slope. Driving tracked equipment up and down the slope creates small speed bumps for water, and can help mulch and seed stay in place. Tracking parallel to the slope will increase erosion rates from the channelized water flow. This technique is very economical with the proper machinery and can save lots of time in the end by reducing maintenance time for sediment removal.
This permanent erosion control method utilizes deliberately placed stones and rocks to dissipate water energy. Riprap should be placed where vegetation cannot withstand high channelized flow. Rock diameter and mass changes depending on predicted flow rates. Placement of riprap can drastically change the device’s ability to reduce erosion. It should have an easy transition between soil and rock, if placed too high, it can channelize the water to cut into the channel and actually increase the erosion rate.
Here is an example of a storm drain inlet protection device. This is a temporary control technique that’s used to capture sediment-laden stormwater from entering the storm drain and storm sewer system. This reduces the need to clean out the pipes at the end of the project. Once all sources with potential for discharging into the inlet have been stabilized, remove the device and install erosion control practices around the inlet. Make sure to routinely check and clean these devices, they are subject to high intakes of stormwater that can displace the device making it ineffective. As you can see, this particular inlet protection device has already stopped a large amount of sediment and the area should be maintained.
Practicing these best management techniques benefits everyone. To see which control methods are best suited for your construction project, check down below in Additional Resources for guides on everything from what it is to how to install it, technical standards required by the DNR, permit compliance and application, techniques to develop erosion and stormwater management plans, and much more!
Addition Resources
Click to view a comprehensive guide on sediment and erosion control techniques and strategies.
Resources for Sediment and Erosion Control Devices and Techniques
Wisconsin Construction Site Erosion Control Field Guide
This expansive field guide on sediment and erosion control Best Management Practices gives detailed descriptions and pictures of the various control devices and techniques. Updated in 2019, it provides definitions, purposes, conditions for application, and installation methods. Highly recommended for anyone doing a construction project.
Technical Standards, Permit Compliance, and Management Plan Design
To help facilitate sediment and erosion control with stormwater management, this WI Department of Natural Resources (DNR) resource provides insight for state-based technical standards to meet, how to predict the types and amounts of pollutants that enter stormwater from the construction project, and the effectiveness of the stormwater management plan.
To successfully merge sediment and erosion control plans with stormwater management plans, it’s important to know how one affects the other. This DNR based resource bridges that gap and helps structure the different managing strategies to work in tandem with one another.
Before any construction can begin, a Notice of Intent must be sent to the DNR for approval. This resource explains how and when to apply for a permit, cost and coverage of the permit, and any additional permits that may be needed (on sensitive land like wetlands for example).
A unique and insightful perspective on managing stormwater for construction sites. Learn the lifecycle and milestones of any project you should be conscious of, the importance of specialized teamwork, and how proper advanced planning can create significant benefits to the work site.
Erosion Control for Home Builders
These DNR and University of Wisconsin Extension resources provide useful information regarding construction for homes and family dwellings in greater detail.
Provides general information and impacts that home building construction has on sediment pollution.
Provides a checklist, best management strategies to include, and regulations to follow. Specifically for 1 and 2 family dwelling construction projects.
General Information
General Information on sediment and sediment pollution/effects by the EPA.
Respect Our Waters
info@respectourwaters.org
Milwaukee area offices:
600 East Greenfield
Milwaukee, Wisconsin 53204
414.382.1766
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