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STORMWATER: OPERATION & MAINTENANCE DETENTION BASIN GUIDE City of Springfield • Department of Environmental Services 290 E. Central St. Springfield, MO 65802 • 417.864.1996 springfieldmo.gov/stormwatermaintenance TABLE OF CONTENTS What is a Detention Basin? 3 Detention Basin Basics 3 Basin Responsibility 3 CONTACTS City of Springfield Types of Basins 4 Department of Environmental Services Stormwater | Water Quality Division Anatomy of a Basin 4 290 E. Central St. How to Care for a Detention Basin 5 Springfield, MO 65802 REPORT POLLUTION (417) 864.1011 Developing a Maintenance Plan 5 Easy Ways to get Started 6 SOCIAL MEDIA Vegetation Management 6 How to Improve an Existing Basin 7 Retrofits and Enhancements 7 QUICK LINKS Glossary of Words & Terms 8 springfieldmo.gov/stormwater Self Inspection List 9-12 springfieldmo.gov/environment INTRODUCTION Purpose of this Guide This is intended to be utilized as a practical aid to inform, educate and assist in the ongoing maintenance and inspections recommended for responsible operation of a detention basin. This guide has been created to detail the different forms of basins, their anatomy, address responsibility inquiries, provide operational and preventative maintenance tasks and a self-inspection checklist. City Code Chapter 96 Article 1 Division 2 Section 96-14 (a) All stormwater control measures and stormwater drainage systems shall be operated and maintained by the responsible party so as to prevent any nuisance conditions and to ensure full functionality, as designed, and in conformity with any approved stormwater plans and any approved operation and maintenance plan and agreement. (b) Operation and maintenance of all stormwater control measures constructed subsequent to the adoption of this article shall be ensured through the creation of an operation and maintenance plan and agreement which shall meet all applicable requirements set forth in the flood control and water quality protection manual and shall be approved prior to construction of the stormwater control measures. (G.O. No. 6445, § 1, 4-9-2018) This guide was prepared by the Stormwater Division of the City of Springfield’s Environmental Services Department. All photographs and graphics created by departmental staff. Created in August of 2019. Get the basin basics here. WHAT IS A DETENTION BASIN? Basin 101 A detention basin is a specifically designed stormwater control measure (SCM) that is intended to reduce the impacts of pollutants in stormwater runoff, while simultaneously holding stormwater during heavy rain periods and increased snow melt in order to slow the rate of stormwater and minimize the potential for flooding and erosion problems downstream. Why are they built? Basins exist naturally, but detention basins are specifically engineered depressions that are built to temporarily collect the increased stormwater runoff created in a developed residential or business area. The construction of homes, streets, sidewalks, driveways and buildings alters the natural landscape and decreases the surface area that previously soaked in water from rains and snow melt. As a result, stormwater runoff increases and can create issues with flooding and erosion. Where are detention basins located? Detention basins can be located on commercial and even private residential property. This can be a residential home or within a residential area maintained by a homeowners association (HOA). Cooper Park Basin responsibility. Who is responsible for the detention basin? Whether you are an individual property owner, an HOA representative or property manager, if the basin is on your property, the responsibility of the basin structure would be yours to maintain and ensure continual longterm operation. Routine maintenance will improve the performance and appearance, while also prolonging the life of the basin, keeping our community safe from flooding and our waterways clean. STORMWATER: DETENTION BASIN • OPERATION & MAINTENANCE • 3 Know how to spot a basin. WHAT IS A DETENTION BASIN? Types of Basins There are different types of basins to help with controlling stormwater. Some are designed to permanently hold a reservoir of water and others serve to collect stormwater, during increased rain and snow melt, in order to filter and slowly release into our waterways. • Retention Basin, or wet detention basin, are designed to permanently hold a reservoir of water. They are essentially, man-made ponds built with vegetation around the perimeters in order to minimize or prevent erosion of the basin structure. Additionally, they provide flood control and water quality benefits. See page 6 for Vegetation Management. • Water Quality Basin, or extended dry detention basins, are designed to collect stormwater during increased rain fall or snow melt and slowly release it, allowing debris and trash to settle or filter out before draining to a nearby waterway. This guide primarily focuses on these types of basins. • Flood Control Basins are designed to reduce flooding downstream by holding stormwater and slowly releasing it. These basins do not provide a significant water quality benefit but can be retrofitted to do so. Anatomy of a Basin Concrete/ Trash Rack Grass Paved Surface Water Detention Level Embankment Well Screen & Perforated Plate Outlet Pipe Concrete Outlet Basin Floor Rock Pile Structure *definitions listed on page 8 Think of it as a large bathtub... that holds the stormwater runoff from sidewalks, roads and parking lots after a heavy rain. The stormwater drains out of the basin much like it would in a tub; dirt and debris being held in the tub once the water drains is identical to how a basin allows trash, debris and pollutants to settle to the basin floor or filter out before being released into a nearby waterway. Once a tub has been drained, the dirt and debris can be seen on the floor or as a ring of grime around the drain. As you would clean this out of a tub, those pieces of trash and debris in a basin would also need to be periodically removed and cleaned out. STORMWATER: DETENTION BASIN • OPERATION & MAINTENANCE • 4 Keep your basin maintained. HOW TO CARE FOR A BASIN Why is basin maintenance important? Properly maintained basins decrease the likelihood of pollutants reaching our waterways and minimize the potential for flooding and erosion. When a basin is not cared for it is not only a visual nuisance, but it can cause an array of issues to the surrounding area and waterways. Not to mention, the cost to repair a basin that no longer functions can be very expensive. Developing a maintenance plan Detention Basin Design When developing a maintenance regimen for a basin, it is ideal to obtain a copy of the basin design through a neighborhood homeowners’ association or by contacting our Stormwater Engineering Division by phone at 864.1935. Access Ensure proper access to the basin for regular inspection and maintenance activities. Identify access points that are wide enough for heavy equipment that may be needed for dredging or major repairs. Consider HOA prohibition against homeowners placing fences, outbuildings, landscaping or anything which might interfere accessing a basin for maintenance requirements. The access point may be within a drainage easement that prohibits placing structures within it. Record Keeping When performing maintenance tasks, remember to record all inspections, activities, repairs and associated costs. An inspection checklist has been provided at the end of this guide that can assist in future documentation of operations and maintenance. Costs of Maintaining An effective maintenance program will incur costs and detention basin owners should budget accordingly. Good record keeping can help to determine annual costs more accurately. Owners should set aside money for routine maintenance as well as the occasions when outside expertise or equipment is needed to maintain, upgrade or repair a basin. Conduct Routine Inspections For basins constructed after the adoption of the City’s Flood Control and Water Quality Protection Manual* a self-inspection must be submitted annually to the City. Submit completed inspections to the Water Quality Division by email to [email protected] or via standard mail to 290 E Central St. *The manual was adopted on December 11, 2017 Monthly Inspections Quarterly Inspections Annual Inspections • Remove trash, debris or yardwaste • Remove any considerable • Inspect structural components blocking the inlet(s), outlet(s) and sediment accumulation with and replace any that may be the basin floor. a shovel and wheelbarrow if broken or failing. preventing water flow. • Inspect for erosion and reseed • Replace rock pile if water flow any bare areas. is restricted from yardwaste and • Use inspection checklist to ensure sediment buildup. all components of basin are functional. STORMWATER: DETENTION BASIN • OPERATION & MAINTENANCE • 5 Easy ways to get started. HOW TO CARE FOR A BASIN Basic Housekeeping Tips Not everything involved in the care of a basin requires physical labor, tools or replacement parts. The best way to prolong the life of a basin is by performing simple daily practices such as: Yardwaste Disposal: Lone Pine Recycling Center Leaves, grass clippings and brush should not 3020 S. Lone Pine Avenue be discarded in a basin. Instead, collect these Franklin Ave. Recycling Center. and dispose of at one of the following: 731 N. Franklin Avenue Large brush and and branches are only accepted at the Yardwaste Recycling Center Yardwaste Recycling Center. 3790 S. Farm Road 119, Brookline, MO Yard Care Additives: Fertilizers should only be used if a soil test determines Fertilizers, pesticides and herbicides should that the area is in need of nutrients to promote grass be used in moderation in a detention basin. growth. Excess application of any products could wash off - adding pollution to our waterways. Pesticides and herbicides may be used to manage Contact James River Basin Partnership to see if you invasive species or convert the vegetation to natives. qualify for a free soil test. (417) 836.4847 Chemical Disposal: Vehicle liquids and oils should never be Pet Waste Disposal: discarded in a basin or open water source.
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