Monday, September 14, 2015

District BMP Inspections - What are we Looking for?

By Kendra Fallon, District Inspector Intern

Kendra Fallon, District Inspector Intern

Over this summer, while working for the Watershed District as an inspector intern, I have looked at a lot of Best Management Practices (BMPs). Roughly six hundred and twenty five, to be more precise! I didn’t make it to all of the BMPs in the District this summer, but I’d like to explain how inspections work and give some perspective on the current condition of the District’s BMPs.

There are a variety of types of BMPs in the District, from rain gardens to rain barrels, pervious pavers to native habitats, even the occasional green roof or wet pond. A majority are either rain gardens or infiltration/filtration basins. The BMPs get separated into two categories - permits or Incentive Program BMPs. Our permit program is required when grading or filling activity involves more than one acre of land, or when working with a wetland or floodplain. Our Incentive Program offers financial, educational and technical assistance to public or private landowners implementing BMPs on their property. BMPs that are constructed through our BMP Incentive Program are inspected annually.


An internal grading scale is used when doing inspections, to provide an easy and quick way for staff to see how BMPs are doing when looking through the database. Each BMP is given an A, B, C, or F grade depending on the level of maintenance it needs. We use our online inspections forms to help decide what grade a BMP should receive.

Our inspection forms consist of three sections: general information, questions and photos. The first step is to input general information which includes time and date of the inspection, weather, and rainfall in the last 48 hours among others. There is also a “Maintenance Required” section where the inspector writes in any maintenance that needs to be done to improve the BMP.

The second step is to go through a set of checklist questions about the BMP. These include questions that are specific to the type of BMP you are inspecting; obviously you are going to have different maintenance concerns if you are looking at pervious pavers than if you are looking at an infiltration basin.

Rain Garden Inspection Checklist Questions
We hope to be able to answer 'no' to all questions, indicating no immediate maintenance is required. These questions are specifically for rain gardens. Different questions exist for other types of BMPs.

Finally there is a section to add photos if desired. This can be done out in the field, or added back in the office on the computer. The inspection forms can be edited on the computer after they have been created, to check spelling or add any other comments that were thought of after the inspection.


An 'A' grade simply means that no immediate maintenance is required. The owner of the BMP should just continue their routine maintenance as needed.

A 'B' grade indicates that minimal maintenance is required. I was taught to think of minimal maintenance as “an afternoon’s workload.” Some of the most common minimal maintenance needs we see are weed removal, sediment accumulation removal, inlet/outlet cleaning, and adding or replacing mulch.

Examples of common maintenance issues
Top: Sediment accumulation in inlet grate that needs to be removed.
Left: Exposed soil needs to be covered with 2-3" of mulch.
Right: Inlet grate needs to be cleared of weeds and debris.

A 'C' grade indicates that more extensive maintenance is needed, or “more than an afternoon’s workload.” This would pertain to a BMP that has multiple maintenance issues to fix, need for replanting a rain garden, or fixing major soil erosion.

Examples of BMPs that would receive 'C' grades:

Rain garden with no vegetation

Shoreline restoration with exposed soil leading directly into a pond.

An 'F' grade is given to BMPs that aren’t functioning properly; this most commonly means that the BMP is holding water 48 hours or more after the last rain event. Below is an example of a rain garden that would receive an 'F' grade.

This rain garden had standing water longer than 48 hours after the last rain event.
The presence of cattails suggests it holds water on water on a regular basis.

The next step for a failing BMP normally depends on the regularity of the ponding. If it is something that has recently become an issue but wasn’t in the past the solution might be as simple as removing any sediment accumulation on the bottom of the rain garden. If the BMP has been ponding for a longer period of time (years), it might require removing the vegetation and reworking the soil for better infiltration.

Current Standing of District's BMPs 

A breakdown of the District’s BMPs by grade is provided below. It should be noted that most of the failing BMPs are getting reworked either this summer or next summer.

Incentive Program
 (~250 Inspected)
(~375 Inspected)
A’s or B’s
<1% (2 failing)
4% (17 failing)

This slight difference in grade distribution between incentive program and permit didn’t surprise me too much, just because incentive program BMPs are owned by people that applied to get them, while permit BMPs are required and might not receive quite as much love and care. Another thing to consider is that ownership of permit BMP properties might change, and the new owners might not be aware that they are in charge of the maintenance for the BMP, or that it exists at all.

Overall, the District’s BMPs are looking good! The simplest way to keep your BMP at an A or a B is to do routine maintenance throughout the year, rather than letting it go and letting problems snowball into an even larger headache. Making sure to pull weeds when they are small, replacing or moving mulch to cover areas where it has grown thin, and removing any sediment accumulation from your BMP are some easy maintenance fixes to keep in mind year round to keep your BMP looking its best.

No comments:

Post a Comment