What is an LPDA?
LPDA stands for "Localized Poor Drainage Area." The Village identified these areas as locations prone to flooding due to topography. In other words, LPDAs are areas of land that are bowl-shaped. Stormwater runoff that cannot infiltrate the ground tends to accumulate in LPDAs, creating flooding. Although LPDAs are not recognized by FEMA, Village building codes regulate both LPDAs and floodplains similarly.
LPDAs are primarily located in older neighborhoods (before the late 1970s) that were built up before stormwater regulation codes requiring stormwater detention existed. The purpose of detention basins is to temporarily store excess water during and after a storm that might otherwise flood structures in the area. LPDAs help serve this function as a naturally formed detention basins.
Why does the Village regulate LPDAs while FEMA does not?
The purpose of regulating LPDAs is to help ensure that any new construction will be reasonably safe from flooding and that the work will not adversely affect other properties. Filling in a portion of an LPDA theoretically increases the flood elevation, potentially leading to a higher chance of flooding to adjacent properties.
Are There Any Restricted Property Uses in an LPDA?
General and recreational use of the property is unrestricted. Landscaping and gardening that does not include fill is generally allowed, provided that stormwater drainage patterns are not blocked and erosion does not become a problem. Fill is only allowed within the LPDA if an equivalent volume can be provided on the same parcel. Any permanent structure, including swing sets and other playground equipment, requires a permit when placed in an LPDA. Please refer to Section 26.1303 of the Village Code for more information.
Buildings constructed near, but just outside, an LPDA must have the lowest adjacent grades (the lowest ground elevation next to the foundation) a minimum of one foot above the 100-year flood elevation. For more detailed information, refer to Section 26.505 of the Municipal Code.
Is My Property Located in a LPDA?
To determine whether your property is in or near an LPDA, visit the Village's Parcel Navigator map. Enter your address in the search box in the upper left hand corner. Go to the bottom of the page and click on the "layers" icon (it looks like a stack of papers) to open a box. Click on the "drainage" layer in that box to make the LPDA boundaries visible.
Please note the location of the floodplain on the maps is approximate and based on elevations. To determine the exact location of the floodplain on your property, a topographic survey is required.
For more information contact the Village Stormwater Administrator at 630-434-5460.