Author: Rachel

Clean water starts with understanding where it goes when it rains. Stormwater runoff plays a major role in shaping our communities, our infrastructure, and the health of the Chesapeake Bay watershed. Yet many property owners don’t realize how their own roofs, parking lots, and landscaped areas affect local water quality.

This guide breaks down what stormwater runoff is, why it matters, and what you can do to manage it responsibly.

What Is Stormwater Runoff?

Stormwater runoff is the rain or melted snow that doesn’t soak into the ground. Instead, it flows over hard, impervious surfaces like:

• Asphalt parking lots

• Concrete sidewalks

• Building roofs

• Compacted soil

When water can’t infiltrate the ground, it finds the easiest path downhill – carrying with it whatever pollutants it encounters. This might include:

• Sediment from bare soil or construction sites

• Nutrients from fertilizers or yard waste

• Oil and grease from vehicles and parking areas

• Trash and debris washed from streets

According to the U.S. Environmental Protection Agency (EPA), stormwater runoff is one of the leading causes of water pollution nationwide. The issue isn’t just the quantity of runoff – it’s the quality.

Why Is Runoff a Problem?

In natural environments like forests and meadows, most rainfall infiltrates into the soil. The ground filters and cleans the water before it recharges groundwater or enters nearby streams. But when land is developed, impervious surfaces prevent infiltration.

That change has two major consequences:

1. More Water, Faster

Stormwater moves quickly over pavement and rooftops, collecting volume and speed. This surge in flow:

• Increases flooding risk

• Causes streambank erosion

• Overwhelms storm drains and detention systems

2. More Pollution, Less Filtration

Because the water never filters through soil, pollutants have no chance to settle out. Runoff can carry sediment, oil, heavy metals, pesticides, and bacteria directly into storm drains – and ultimately, into local waterways.

Over time, these pollutants accumulate in downstream ecosystems, damaging aquatic habitats and degrading water quality.

The Connection Between Runoff and the Chesapeake Bay

For communities in Maryland, Virginia, Delaware, and the District of Columbia, every drop of runoff eventually makes its way to the Chesapeake Bay, the largest estuary in the United States.

The Chesapeake Bay Program reports that stormwater runoff is the only major source of Bay pollution still increasing. It carries nitrogen, phosphorus, and sediment – the same pollutants that fuel algae blooms, reduce oxygen levels, and smother habitats for fish, crabs, and oysters.

That means even small changes at the local level – a clogged inlet, an eroding outfall, or a neglected retention pond – can ripple downstream and affect the health of an entire ecosystem.

Understanding the basics of stormwater runoff isn’t just about property management; it’s about protecting the Bay.

Common Types of Stormwater Runoff

While every site is unique, stormwater runoff generally falls into three main categories:

1. Surface Runoff
   Water flowing over the land surface – the most visible type. It occurs when rain exceeds the soil’s ability to absorb it.

2. Subsurface Runoff (Interflow)
   Water that infiltrates shallow soil layers and moves laterally underground toward streams. Though less visible, it can carry dissolved nutrients and pollutants.

3. Urban Runoff
   A specific subset of surface runoff, common in developed areas with lots of pavement and buildings. Urban runoff is often the most polluted and most challenging to control.

How Stormwater Management Helps

Stormwater management aims to slow down, spread out, and soak in runoff as close to where it falls as possible. The goal is to mimic natural hydrology and reduce both flooding and pollution.

Common solutions include:

Green Infrastructure

• Bioretention areas and rain gardens that filter runoff through plants and soil

• Permeable pavers that allow rain to soak through instead of pooling

• Green roofs that absorb rainfall and reduce heat islands

Structural Systems

• Detention and retention ponds that temporarily hold runoff

• Infiltration trenches that allow water to percolate into the ground

• Stormwater filters and proprietary systems that remove pollutants before discharge

Properly designed, installed, and maintained systems reduce the volume and velocity of runoff, protect local infrastructure, and improve downstream water quality – all while helping communities meet EPA and local MS4 permit requirements.

Why Stormwater Runoff Matters for Property Owners

For commercial and residential property managers, understanding stormwater runoff isn’t optional – it’s a responsibility. Improperly managed runoff can lead to:

• Flooding and property damage

• Erosion and landscape loss

• Regulatory violations

• Costly repairs to clogged or failing drainage systems

Routine stormwater inspections and maintenance help prevent these issues. By keeping systems clear, identifying damage early, and maintaining compliance, property owners can protect both their investments and the environment.

The Chesapeake Bay Connection, Revisited

Every storm drain in our region leads to a local stream – and every local stream leads to the Chesapeake Bay. Even if your property is miles from the Bay itself, the stormwater leaving your site contributes to the larger watershed.

That’s why the region’s stormwater permits and best management practices are designed not only to protect your property, but also to restore and safeguard the Bay for future generations.

Key Takeaways

• Stormwater runoff is rainfall or snowmelt that doesn’t soak into the ground.

• Impervious surfaces accelerate runoff, increasing pollution and erosion.

• Runoff is a major pollution source for waterways, including the Chesapeake Bay.

• Stormwater management systems (like ponds, filters, and bioretention areas) help reduce impacts.

• Property managers and owners play a critical role in keeping local waters clean.

Partner With Experts in Stormwater Management

Understanding the basics is only the first step – maintaining effective stormwater systems is what truly protects your property and the environment.

At iSTORMWATER, our team provides stormwater inspections, maintenance, andcompliance services throughout Maryland, Northern Virginia, Washington, D.C., and Delaware. We help commercial property owners meet regulations and reduce their environmental footprint – one drop at a time.

📞 Call us at (410) 231-3455 or 💬 Contact us online.

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Stormwater ponds are vital to managing runoff, improving water quality, and protecting downstream waterways. Found on commercial properties, HOAs, and municipal sites, these engineered systems are designed to capture and treat stormwater before it’s released – often holding water year-round, like a retention or wet pond.

But without routine maintenance, stormwater ponds can quickly lose efficiency and develop issues that affect performance, appearance, and compliance. Below are eight common stormwater pond problems, how to identify them, and how to keep your system functioning at its best.

1. Sediment Build-Up

Sediment naturally settles in stormwater ponds over time as runoff carries soil, debris, and pollutants from surrounding areas. Left unchecked, this buildup reduces pond depth, storage capacity, and water quality – often leading to algae growth and clogging.

Warning signs:

• The pond looks shallower or has visible sediment along the edges
• Murky or brown water after storms
• Slower drainage or water standing near inlets/outlets

How to fix it:

• Schedule periodic sediment surveys and inspections
• Remove excess sediment through dredging or vacuum excavation
• Maintain forebays and erosion controls upstream to prevent further accumulation

2. Algae Blooms

Excess nutrients from fertilizers, pet waste, or decaying vegetation can cause algae to grow rapidly in stormwater ponds – especially those that retain standing water.

Why it matters:
Algae blooms can deplete oxygen, produce foul odors, and create an unsightly surface film. Some blooms, like blue-green algae, can even pose health risks to people and pets.

How to fix it:

• Reduce nutrient runoff by managing fertilizer use
• Maintain a healthy vegetative buffer to absorb nutrients
• Add aeration or fountains to circulate water and reduce stagnation
• Remove nutrient-rich sediment when needed

3. Erosion of Pond Banks

Fluctuating water levels, poor vegetation coverage, and wave action can cause erosion along pond banks. Over time, this weakens structural integrity and increases sediment loading.

Warning signs:

• Exposed soil or roots around the shoreline
• Undercutting, slumping, or collapsing edges
• Bare or uneven slopes

How to fix it:

• Stabilize banks with deep-rooted native vegetation
• Install riprap or erosion control matting in problem areas
• Repair eroded sections promptly to prevent further damage

4. Clogged Inlets and Outlets

Healthy flow in and out of the pond is essential for maintaining water quality and preventing flooding. When debris, vegetation, or sediment blocks these structures, pond function declines.

Warning signs:

• Standing water or overflow after rainfall
• Visible debris blocking inlets or outlets
• Uneven pond water levels

How to fix it:

• Clear trash, leaves, and sediment from inlets/outlets after major storms
• Repair or replace damaged trash racks or grates
• Schedule routine inspections of outlet control structures

5. Excessive Aquatic Vegetation

Aquatic plants play an important role in filtering stormwater, but too much growth can choke the system, restrict flow, and create mosquito-friendly conditions.

Warning signs:

• Dense mats of plants on the surface or around edges
• Reduced water circulation
• Odors or signs of decay

How to fix it:

• Manage vegetation with regular seasonal maintenance
• Remove excessive growth mechanically or through approved aquatic treatments
• Maintain nutrient balance and circulation to prevent overgrowth

6. Mosquito Breeding

Stormwater ponds that remain stagnant or collect debris can become mosquito breeding grounds, especially in warmer months.

Warning signs:

• High mosquito activity around the pond
• Stagnant areas or surface scum
• Floating debris or decaying vegetation

How to fix it:

• Improve water movement with aeration or fountains
• Remove floating debris and decaying plant material
• Introduce fish species that feed on mosquito larvae (where appropriate)

7. Structural Damage

Stormwater ponds rely on control structures – such as risers, pipes, and outfalls – to manage water levels. Corrosion, cracking, or blockages can reduce performance or lead to failure.

Warning signs:

• Rusting, cracks, or settlement around outlet structures
• Leaks or inconsistent water levels
• Damaged or missing screens and grates

How to fix it:

• Schedule annual structural inspections
• Repair or replace failing components
• Use durable, corrosion-resistant materials for long-term performance

8. Trash & Debris Accumulation

Stormwater runoff often carries litter, leaves, and other debris into ponds. Without removal, this buildup clogs structures, reduces storage volume, and degrades water quality.

Warning signs:

• Floating debris or scum near inlets/outlets
• Discolored or odorous water
• Reduced water movement after rainfall

How to fix it:

• Implement regular debris removal
• Install trash racks or floating skimmers
• Educate property users about preventing litter runoff

Why Stormwater Pond Maintenance Is Essential

Routine stormwater pond maintenance ensures your system:

• Remains compliant with local and state stormwater regulations
• Protects against flooding, erosion, and costly repairs
• Preserves water quality and pond appearance
• Extends the lifespan of your infrastructure

Whether your pond holds water year-round or drains periodically, professional inspection and upkeep are key to keeping it functioning as designed.

Partner With iSTORMWATER for Stormwater Pond Maintenance

At iSTORMWATER, we provide comprehensive inspection, maintenance, and repair services for stormwater ponds across Maryland, Northern Virginia, Washington, D.C., and Delaware.

Our experts identify and resolve issues like sediment build-up, erosion, algae, and structural wear – keeping your pond clean, compliant, and effective.

Contact iSTORMWATER today to schedule a stormwater pond inspection or learn more about our maintenance programs.

📞 Call us at (410) 231-3455 or 💬 Contact us online.

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Why Stormwater Management Matters for Schools

University and school campuses often resemble small cities. With large parking lots, athletic fields, sidewalks, and rooftops, these institutions generate significant amounts of stormwater runoff. Without proper stormwater management, campuses can face flooding, erosion, property damage, and water quality issues that impact both the environment and the community.

Beyond compliance with federal, state, and local stormwater regulations, schools and universities have the opportunity to lead by example – integrating green infrastructure and innovative stormwater solutions that benefit students, staff, and surrounding neighborhoods.

Stormwater Challenges on Campuses

Educational campuses present unique stormwater management challenges:

• High Impervious Surfaces: Parking lots, dorms, academic buildings, and walkways create large areas where rainwater cannot infiltrate naturally.
• Heavy Foot and Vehicle Traffic: Runoff carries pollutants like oil, heavy metals, trash, and nutrients from vehicles and pedestrian activity.
• Athletic Facilities: Sports fields and stadiums often require turf and drainage systems that impact stormwater flow.
• Aging Infrastructure: Many schools operate with outdated stormwater systems that no longer meet modern standards.
• Regulatory Compliance: Universities and school districts must comply with local Municipal Separate Storm Sewer System (MS4) permits and state-level stormwater regulations.

Effective Stormwater Solutions for Schools & Universities

1. Green Infrastructure

Green infrastructure uses natural systems to absorb, slow, and filter stormwater:

• Bioretention Facilities & Rain Gardens: Planted depressions that collect and filter runoff, improving campus aesthetics while controlling flooding.
• Green Roofs: Vegetated rooftops reduce runoff, insulate buildings, and create outdoor learning spaces.
• Permeable Pavements: Used for walkways, parking lots, and courtyards to allow water to soak into the ground instead of overwhelming storm drains.

2. Stormwater Ponds & Basins

Retention and detention ponds capture runoff during storms. On campuses, these can double as educational tools for biology or environmental science classes. Proper maintenance – such as sediment removal and vegetation management – is critical to keep them functioning effectively.

3. Underground Systems

When space is limited, underground detention systems or vaults can be installed beneath athletic fields or parking lots, storing runoff and slowly releasing it to prevent downstream flooding.

4. Oil Grit Separators & Filters

Parking lots near student housing, stadiums, or staff facilities benefit from devices like oil grit separators, hydrodynamic separators, and proprietary filters (e.g., Contech StormFilter®). These remove sediment, oil, and pollutants from “first flush” runoff.

5. Routine Inspections & Maintenance

Preventative maintenance is essential for keeping stormwater systems working:

• Regular inspections of inlets, drains, and pipes.
• Clearing sediment and debris.
• Replenishing mulch and vegetation in bioretention areas.
• Monitoring erosion near athletic fields and construction zones.

Benefits of Campus Stormwater Management

Implementing stormwater solutions goes beyond regulatory compliance. Schools and universities can achieve:

• Improved Safety: Reduced flooding and icy conditions on walkways and parking lots.
• Environmental Protection: Cleaner rivers, lakes, and watersheds benefiting surrounding communities.
• Long-Term Cost Savings: Preventative maintenance is far less expensive than repairing damage from flooding or system failures.
• Educational Opportunities: On-campus stormwater facilities can serve as living laboratories for students studying environmental science, engineering, or sustainability.
• Positive Community Image: Demonstrating environmental stewardship enhances a school’s reputation and can support LEED or sustainability goals.

Compliance Considerations for Universities & Schools

• MS4 Permits: Many universities are considered non-traditional MS4s and must follow federal Clean Water Act guidelines.
• State & Local Requirements: Regulations vary by state (e.g., Maryland Department of the Environment, Virginia DEQ, Delaware DNREC).
• Construction Projects: New buildings or expansions require erosion and sediment control plans to minimize impacts during development.

Partnering With Stormwater Experts

Stormwater management requires a blend of engineering, maintenance, and regulatory expertise. Partnering with a professional stormwater management company ensures:

• Systems are designed to meet local and federal regulations.
• Maintenance is performed on schedule.
• Emergency issues (clogged drains, flooding, erosion) are resolved quickly.

Universities and schools have a responsibility to manage stormwater effectively – not only to comply with regulations but also to protect students, staff, and surrounding communities. By investing in green infrastructure, updated stormwater facilities, and regular maintenance, campuses can transform stormwater challenges into sustainable solutions that inspire the next generation of environmental leaders.

📞 Call us at (410) 231-3455 or 💬 Contact us online.

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Stormwater facilities – including ponds, bioretention cells, bioswales, and infiltration basins – are designed to filter pollutants, slow runoff, and protect waterways. But when invasive plants take hold, these facilities can lose effectiveness and require costly maintenance. Across Maryland, Northern Virginia, Washington, DC, and Delaware, invasive plants threaten both stormwater infrastructure and the health of the Chesapeake Bay.

This guide explains how to identify invasive plants in stormwater facilities, why they’re problematic, and which native alternatives thrive in our region.

Why Invasive Plants Are a Problem for Stormwater Systems

Invasive species spread aggressively and outcompete native plants, disrupting the balance that stormwater best management practices (BMPs) depend on.

Key impacts include:

• Reduced performance and clogged structures
• Increased erosion and slope instability
• Loss of biodiversity and wildlife habitat
• Higher maintenance costs
• Local regulatory restrictions on invasive species

Invasive Plants to Watch in Maryland Stormwater Facilities

Maryland stormwater ponds and bioretention areas often struggle with:

• Phragmites australis (common reed) – creates tall, dense monocultures in wet zones
• Japanese stiltgrass (Microstegium vimineum) – overtakes swales and shaded buffers
• Multiflora rose (Rosa multiflora) – orms thickets that block maintenance access

The Maryland Invasive Species Council lists these and many more plants that threaten stormwater function across the state.

Invasive Plants in Northern Virginia Stormwater Ponds and Bioswales

In Northern Virginia, invasive vines and shrubs are especially common:

• Oriental bittersweet (Celastrus orbiculatus) – smothers trees and structures
• Japanese honeysuckle (Lonicera japonica) – spreads along pond banks and buffers
• Tree of heaven (Ailanthus altissima) – sprouts aggressively and damages infrastructure

The Virginia Department of Conservation and Recreation (DCR) provides invasive plant lists and guidance for landowners.

Invasive Plants Threatening DC Green Infrastructure

Washington, DC has invested heavily in green infrastructure projects like rain gardens and bioswales. Unfortunately, these systems are vulnerable to:

• English ivy (Hedera helix) – a common groundcover that quickly invades facilities
• Porcelainberry (Ampelopsis brevipedunculata) – a fast-growing vine often mistaken for grape
• Japanese knotweed (Fallopia japonica) – spreads by rhizomes and can damage hardscape structures

In urban stormwater sites, invasives not only block water flow but can also compromise engineered soils and designed planting plans.

Invasive Plants in Delaware Stormwater Management Facilities

Delaware’s stormwater ponds and ditches are especially prone to:

• Purple loosestrife (Lythrum salicaria) – produces thousands of seeds and overtakes wetlands
• Japanese stiltgrass – a regional problem in shaded slopes
• Callery pear (Pyrus calleryana) – spreads from landscaping into stormwater buffers

The Delaware Department of Natural Resources and Environmental Control (DNREC) offers best practices for invasive plant removal and native replacement.

Native Plants for Stormwater Facilities in the Chesapeake Bay Region

Replacing invasives with native species not only protects stormwater function but also supports Bay restoration goals.

Wet Edges & Shallow Water

• Blue flag iris (Iris versicolor)
• Pickerelweed (Pontederia cordata)
• Buttonbush (Cephalanthus occidentalis)
• Soft rush (Juncus effusus)

Slopes & Buffer Zones

• Switchgrass (Panicum virgatum)
• Joe-Pye weed (Eutrochium purpureum)
• Winterberry holly (Ilex verticillata)
• Black-eyed Susan (Rudbeckia hirta)

Upland or Drier Zones

• River birch (Betula nigra)
• Red maple (Acer rubrum)
• Eastern red cedar (Juniperus virginiana)
• Common milkweed (Asclepias syriaca)

These native species stabilize soils, filter runoff, and provide food and habitat for pollinators, birds, and other wildlife.

Stormwater Facility Management Tips for Property Owners

• Inspect facilities at least three times per year (spring, summer, fall).
• Remove invasive seedlings early before they spread.
• Replant disturbed soil with fast-growing natives.
• Require contractors to use weed-free seed mixes and mulch.
• Document problem areas and schedule follow-up maintenance.
• Partner with professionals who understand both stormwater regulations and invasive species management.

Conclusion

Stormwater facilities in Maryland, Northern Virginia, DC, and Delaware are vital to protecting the Chesapeake Bay – but invasive plants threaten their effectiveness. By identifying invasives early and replanting with strong native species, property managers can protect water quality, reduce maintenance costs, and improve facility resilience.

👉 Need help with invasive plant control in your stormwater ponds, swales, or bioretention areas? Our team provides inspection, maintenance, and native planting services throughout the Chesapeake Bay region.

📞 Call us at (410) 231-3455 or 💬 Contact us online.

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Erosion is one of the most persistent challenges in stormwater management. Without proper controls, runoff can carry away valuable soil, clog drainage systems, and pollute nearby streams, rivers, and lakes. One of the most effective – and often overlooked – tools for slowing stormwater and preventing erosion is the check dam.

In this article, we’ll explore what check dams are, how they work, and why they are an important part of erosion and sediment control strategies for commercial properties, construction sites, and municipal stormwater systems.

What Is a Check Dam?

A check dam is a small, temporary or permanent barrier constructed across a drainage channel, swale, or small waterway. Unlike large dams, check dams are designed to be low-cost, low-profile structures that:

• Slow stormwater flow in ditches or channels
• Reduce erosive velocity of runoff
• Capture sediment before it reaches downstream waterways
• Encourage infiltration into the soil

Check dams can be made from a variety of materials, including:

• Rock or riprap (most common in permanent applications)
• Sandbags (for temporary projects)
• Logs, brush, or timber
  
• Wattles or compost filter socks
  
• Concrete or gabions (engineered for higher durability)

How Check Dams Reduce Erosion

The main goal of a check dam is to disrupt the energy of flowing water. Fast-moving runoff has the power to cut into soil, destabilize slopes, and transport large amounts of sediment downstream. By breaking up flow in stages, check dams help:

1. Decrease water velocity – slowing stormwater prevents scouring of channels and gullies.
2. Trap sediment – particles carried in runoff settle out behind the dam.
3. Promote infiltration – water pools temporarily, giving it more time to soak into the ground.
4. Protect infrastructure – stabilized drainage channels help prevent costly repairs to stormwater systems, roads, and landscaping.

Common Applications for Check Dams

Check dams are used across a wide range of stormwater and erosion control projects, including:

• Construction sites – Temporary check dams help control sediment-laden runoff until permanent stabilization is complete.
• Roadside ditches and swales – Prevent channel erosion along highways and commercial properties.
• Slopes and embankments – Useful in steep areas where runoff gains erosive force quickly.
• Urban stormwater systems – Often paired with bioswales or grassed channels to improve water quality.

Design Considerations for Effective Check Dams

While check dams are simple in concept, proper design and placement are critical for effectiveness and compliance with local stormwater regulations. Best practices include:

• Spacing: Install multiple check dams along a channel, ensuring the toe of the upstream dam is level with the crest of the downstream dam.
• Height: Typically less than 3 feet tall to prevent overtopping hazards.
• Anchoring: Materials must be properly keyed into the channel to resist displacement during high flows.
• Maintenance: Regular inspections are necessary to remove accumulated sediment, repair damage, and ensure flow is not bypassing the dam.

Environmental and Regulatory Benefits

Check dams provide both environmental protection and regulatory compliance benefits:

• Help properties meet EPA NPDES stormwater permit requirements by reducing sediment discharge.
• Protect local waterways from excessive nutrient and pollutant loads.
• Support sustainable site management by preserving soil health and stabilizing disturbed areas.

Professional Erosion Control Services

While small-scale check dams can be installed with basic materials, larger projects or sites subject to strict stormwater regulations require professional design and maintenance. Partnering with an experienced stormwater management team ensures check dams are properly sized, installed, and maintained for long-term performance.

📞 Call us at (410) 231-3455 or 💬 Contact us online to discuss stormwater solutions tailored to your site.

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Key Takeaway

Check dams are a cost-effective and practical erosion control tool that can play a vital role in stormwater management. By slowing runoff, capturing sediment, and protecting drainage systems, they help safeguard both property and the environment.

Whether on a construction site, a roadside channel, or a commercial property, properly designed check dams should be part of any comprehensive erosion and sediment control plan.