Heavy rain exposes every weak point in your stormwater runoff management plans. Water will always follow the fastest path downhill, and it carries sediment, debris, and pollutants with it. Take care to cover all angles of sediment bypass prevention, because if runoff overwhelms drains and low spots, compliance issues and cleanup can be expensive.

Never wait for the forecast to change before you think about stormwater runoff control. Put the time in to identify potential problem areas in advance so you can install appropriate controls for your inlets and site layout.

Here are six ways to improve runoff performance before the next storm rolls in.

1. Identify the Most Likely Runoff Pathways

Since water always finds the low point, likely runoff patterns can be mapped before heavy weather arrives. Walk the site before major rain events and identify:

• Low spots & curb flow concentration points
• Areas with exposed loose soil (especially slopes)
• Unfinished grading
• Specific storm drain inlets that are likely to receive the heaviest flow
• Locations where runoff may bypass controls

Conditions change constantly during construction, so review regularly. A drainage path that didn’t exist two weeks ago may become the biggest sediment problem on-site after the next storm. The earlier those issues are identified, the easier they are to control.

2. Match Inlet Protection to Flow Conditions

High-flow areas often require stronger filtration systems and overflow protection to prevent bypass. Temporary geotextile inserts, curb inlet filters, and below-grate filtration systems can all play a role depending on inlet type and runoff volume.

Catch basin inserts and geotextile fabric-based inlet protection are specified in federal guidances from the EPA as an effective temporary BMP because it slows runoff while capturing sediment before water enters the system. Many guidances from local state agencies and organizations, such as the California Stormwater Quality Association (CASQA), also highlight reusable geotextile inserts, which are installed beneath grates or inside curb inlets, as practical temporary protection solutions. They’re easily removable, and many can even be cleaned and reused.

3. Use Gravel Bags and Wattles Correctly

Gravel bags and wattles can be good solutions for slowing runoff before it reaches the inlet. One common mistake, though, is placing them directly over the grate. This can block drainage entirely and create flooding issues. Instead, position them securely near and around the inlet to create temporary ponding that allows sediment to settle out before water enters the drain.

Heavy-duty geotextile gravel bags like our Dandy Recycler, filled with recycled rubber, are perfect for filtering out sediment like a pea-gravel-weighted wattle, but they’re easier to install and reuse. 

Deploy layered stormwater runoff control around curb and gutter inlets during larger rain events to stop the transport of sediment into stormwater systems and keep drainage flowing.

4. Inspect Inlet Protection Before and After Storms

A protection system that worked last month may not survive the next rain event without maintenance. Inspect all inlet protection before storms arrive and immediately afterward. Many state guidances, such as this one from Ohio, specify that protection devices placed on an inlet draining pavement must “be cleaned after every runoff-producing rain event” — and for good reason. Lapses in maintenance with built up sediment in the receptacle is a common cause of compliance issues and sediment bypass. Look for:

• Sediment buildup
• Torn geotextile fabric
• Shifted or collapsed barriers
• Water bypass around edges
• Standing water caused by clogging

Crews sometimes underestimate how quickly sediment builds up during consecutive rain events. Most inlet protection systems should be cleaned once accumulated sediment reaches roughly half the height of the barrier or half the depth of the containment area. Waiting longer increases the risk of bypass, overflow.

Pre-storm inspections help crews catch weak points before they fail under heavy runoff conditions, but post-storm checks are just as important.

5. Always Review Local Stormwater Requirements

Many construction crews are used to working across multiple municipalities. Keep in mind that stormwater sediment protection guidelines and regulations vary widely between cities, counties, and state agencies. An inlet protection plan that meets compliance requirements on one project may not meet requirements somewhere else.

Before your project breaks ground, be sure to review local guidance and confirm your site is meeting current environmental and zoning expectations for temporary runoff control, inlet protection, sediment containment, and inspection schedules (specific preferred language for these measures may vary by region).

This step is often overlooked on fast-moving projects. Don’t fall into that trap. Take time to confirm local requirements and head off potential inspection issues.

Stormwater Runoff Control Starts Before the Forecast Changes

Dandy Products helps contractors manage runoff and meet NPDES II compliance with durable inlet protection solutions. Our orange Dandy products are recognizable anywhere. If it’s not orange, it’s not Dandy! The advanced geotextile fibers of our drop inlet bags and curb-mounted solutions will handle sediment-laden runoff over and over again — and they’re easy to clean and reuse from site to site. 

Give us a call or drop us a line. Our experts will review your project specifications and quickly guide you to the most effective solution for your application.

FAQs About Stormwater Runoff Management

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