Clean Water Detention Pond

Stormwater Detention Ponds

Romtec Utilities engineers a lot of stormwater pump stations. These systems are used for several different purposes, and before any engineering takes place, it is important to understand the application of the system. So, let’s take a look at applying a pump station to a detention pond system for stormwater.

A detention pond can be thought of in two ways. The first is a pond that takes in stormwater but needs to be pumped to prevent overflow during a stormwater event. The second is a pond that is large enough to “handle the event” and then pumps out at a preset rate afterward.

In the first situation, the wet well will commonly be large in order to accommodate large amounts of stormwater flowing from the detention pond. Pumps for this type of system might also be large in terms of horsepower, or the design could specify more efficient pumps for stormwater like vertical turbine pumps. Here, the design typically would specify duplex or triplex pump configurations (2 or 3 pumps) to allow pumping in multiple cycles. Another approach is to include Variable Frequency Drives (VFDs) to match the unpredictable inflows.

In the second situation, the wet well will typically not be large. Since the pond is sized to contain a stormwater event, the pump station will only need to empty it. The simplest solution is to put in two pumps that will discharge at a known rate to disperse a known volume of water.

SMUD Stormwater Detention Pond

Matching The Design To The Scenario

In both of these scenarios, the wet well can be configured in rectangular or round precast concrete. To select the size and shape of the wet well, two aspects are important: the size of the total system and the location of the system. Rectangular sumps will typically be used in areas where deep underground excavation is not possible and in systems with numerous in-well components. Round wells are appropriate for the majority of detention pond systems because of their widespread use and familiarity.

In any stormwater system with a detention pond, Romtec Utilities will start by asking which of these two scenarios your project fits in to. With that knowledge, our engineers can design and propose the best practices for engineering a package stormwater pump station.

We can pump to and from detention and retention ponds with expert pump station designs that will function to meet your needs on your specific site. Our experience will help you get a long-term pump station solution for the management of your detention pond.

Preparation For Major Stormwater Events

Your detention pond might fill up and need to be emptied at a specific pumping rate. It may also need to pump to “keep up” with major storm events. Romtec Utilities will design your detention pond pump station to function perfectly in your required conditions.

The Crystal Creek project was a 23-acre mixed-use community development that needed a stormwater pump station with a detention pond in Texas.

The purpose of the pump station was to handle medium flows of stormwater from the development. The system features a flooded inlet line, allowing the precast concrete wet well to be installed at a shallower depth. A flooded inlet line allows the pump station to be installed at a shallow depth, marginalizing the construction costs associated with digging a hole.

There are two 5 hp Ebara pumps in a duplex configuration to meet the pumping rates, a series of floats to measure the in-well levels, and a UL-listed alternating control panel operates to start and stop pumps on level. This pump station is designed to pump discharge into a detention pond.

With flash flooding in Texas, it’s important for developments to have a plan in order to handle storm event flows and one way is to incorporate a detention pond.

If you are looking at completing a stormwater pump station with a detention pond in Texas or anywhere nationwide at Romtec Utilities we can design, manufacture, and supply your system.

Stormwater Pump Station Discharging into Groundwater Retention Basin

Where To Install In Relation To The Detention Pond

There is one other consideration when designing a stormwater pump station with a detention pond and that is where to install the system in relation to the pond. Whether that is in the berm or in the pond, matters when it comes to the final cost and various features.

Installing a pump station in the berm is almost always the best solution because it involves simple designs, common components, and easier long-term maintenance.

Designing a pump station in the berm avoids extraneous design scenarios that include access to the station, system maintenance, and the structural nature of the wet well. Although putting a system in the berm requires additional underground construction or intake structures it still avoids those other challenges.

Providing an easily accessible pump station means that personnel will have access to various components without any issues. Also, vehicles with other components needed to fix or repair a pump station will have access if on a berm compared to inside the detention pond.

Lift stations in the berm can be easily maintained because all of the components are accessible and engineered in a typical configuration. This means components like cable trays, disconnect stands, and valve vaults can all be utilized to make maintenance simple. Putting a pump station in the pond itself costs more due to the difficult design features and work it requires to outfit the system in that location.

Lift Stations In The Berm

The typical precast concrete used by Romtec Utilities is designed to be installed in the ground. In this application, it is generally the most affordable structural solution.

In the pond, the wet well can be a free-standing unit or submerged. Precast concrete is not designed to free stand, requiring higher-cost cast-in-place concrete, fiberglass, or steel wells instead.

All of these considerations point to installing the stormwater pump station in the berm adjacent to the pond to help with the overall cost, accessibility, maintenance, and structure of the wet well.

At Romtec Utilities we can design and supply your stormwater pump station with a detention pond whether its pumping into a pond or out of it. Our design experience can help make this necessary component feasible and construction friendly.

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