Brookings approves master drainage plan

BROOKINGS A new 10-year master drainage plan, whose goals include reducing the flood risk within the city, was accepted on a 7-0 vote by the Brookings City Council on Tuesday night.

The ISG-authored plan, which has been in the works since August 2021, splits the city into five drainage areas Central, Medary, SDSU, Southwest and I-29S and outlines improvements in each, with special attention paid to Central, Medary and SDSU. Recommended projects include:

SDSU drainage area

• Rotary Park improvements
• Village Square conveyance, plus storage improvements
• State Avenue plus US Highway 14/Sixth Street storm sewer improvements

Medary drainage area

• Eighth Street South storage
• Nelson storage plus conveyance improvements
• 32^nd Street storage plus upstream conveyance improvements
• Sawgrass Drive storm sewer improvements
• Parkway Boulevard storm sewer improvements

Central drainage area

• Brookings Regional Airport storage
• Pioneer Park improvements
• Fifth Avenue underground storage plus storm sewer improvements
• Veterans Memorial Park plus storm sewer improvements
• Third Street storm sewer improvements.

Altogether, the plan contains $45 million in project recommendations. Since money is always an issue, the city will focus on what it can afford which is, at the moment, $12 million in projects over the next 10 years, ranging in price from $380,000 to $4,980,000. In addition to a green infrastructure incentive for properties and neighborhood improvements, attention will focus on:

• 32^nd Street detention design and construction
• Village Square conveyance improvements
• Fifth Avenue underground storage
• Veterans Memorial Park plus storm networks improvements

Even with a reduced focused by the city planning for $12 million in work instead of the full $45 million in recommendations from ISG funding will be a paramount issue. No loans will be used and grant funds will be sought, but this is also where the citys stormwater fee comes into the picture, and its likely going to change.

Right now, the fee relies on land use cropland, commercial, industrial, homes, those sorts of things and the square footage of the parcel in question to calculate an assessment. ISG is recommending that the city switch to a fee system called Equivalent Residential Unit. Its a system used by 80% of the communities in the U.S. that collect a stormwater fee, per presentation materials at Tuesday nights meeting.

Basically, ERU uses infrared technology to determine a lots imperviousness, a factor which plays a role in higher runoff and a greater need for infrastructure to handle said runoff. Long story short, a fee based on the ERU correlates the amount of actual impervious area on a lot to the runoff volume it produces.

Two examples were shown using the new ERU system:

• In the first one, a 51-acre parcel with 13 acres of impervious area would be considered 25.5% impervious. Its current annual bill is $23,604; with ERU in force, it would decline to $9,351.47.
• In the second one, a 12.8-acre parcel with 12.1 acres of impervious area would be considered 94.1% impervious. Its current annual bill adds up to $6,723; with ERU, that total would rise to $8,670.66.

If its implemented in Brookings, each single-family residential property would pay a stormwater fee thats the equivalent of one ERU. The ERU is based on an average single-family residential impervious area of 4,573 square feet as determined by an infrared flyover. Non single-family residential property fees would depend on the parcels impervious area.

Here comes the dollars-and-cents part of the equation. The proposed stormwater fee, based on an ERU, means Brookings residents:

• Would pay $6.14 per month, effective in 2025
• Its an increase of 4.24% for an average single-family residential property, with the last increase having taken place in 2019
• Starting in 2026, the annual rate increase would be 3%
• The changes would bring in an estimated extra $300,000 per year, which in turn would help with the aforementioned projects in the 10-year plan
• The fee would be billed with the property tax

Changing over to an ERU system requires a revision to the citys storm drainage ordinance, and the first reading of that took place Tuesday night. The second reading is set for the Aug. 27 meeting of the City Council.

I really appreciate the work thats been done on this to be able to see the forward thinking and the plan to be able to address some of our stormwater issues is really fantastic and to see the way sustainability has been woven into this is really encouraging, Councilor Holly Tilton Byrne said after the presentation.

In other business on Tuesday night:

• On a 7-0 vote, approved a bid from Austreim Excavating LLC to replace the northern bridge on Western Avenue. The project will cost $166,489.94 coming in roughly 22% lower than the engineers estimate of $213,420 and will see the bridge replaced with three, 30-inch culverts. The expected completion date is by the end of October.
• Approved, again on a 7-0 vote, a $174,412 low bid for a 4,000 gallon water truck from Custom Truck One Source. The bid was roughly 14% lower than the $200,000 that was budgeted for the acquisition.

Contact Mondell Keck at [email protected].