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ENGINEERING AND PUBLIC WORKS
One Thing Leads to Another
Have you ever wondered why Public Works projects sometimes stop short of completing an entire job,
start in the wrong place, didn’t do the worst part first, or seemed to leave out something along the way? Sometimes mistakes are made, but often these types of things occur because the plans for two or more projects are intertwined and funding is only available for one or only part of one. The following is a real life example of an O’Fallon infrastructure plan involving multiple, related projects.
 When homes were originally built in the 400 and 500 blocks of E. Washington, the City had no public works or code enforcement involvement in subdivision design. At the time, no one considered how the height of the road bed in front of the homes would some day affect the quality of life of those living there. As a result, we now have a road that has numerous large puddles and
even floods yards for extended periods after a rain. In some places the water has nowhere to go and just ponds until it evaporates.
The estimate to remedy the drainage problem in this two block area is $390,000. The proposed project will completely reconstruct the roadway along these two blocks, lowering the roadbed to allow the front of the residential lots to drain toward the street. The new  pavement will be 30-feet wide from back of concrete curb to back of concrete curb. This roadway section will
be exactly like that of the roadway that developers are required to install in new subdivisions. Along with the roadway construction, the sidewalks in poor condition will be replaced and new concrete driveway entrances will be provided. There are 39 residential properties along these two blocks.
The $390,000 project replaces the roadway system and provides a new underground drainage system for taking stormwater from the road surface and adjacent yards. You may be wondering where this stormwater will go as there is no other underground or ditch storm system to take the flow. The answer is that we need a collection pit and a stormwater main to get it to the nearest natural stream reach.
To provide points for collection of stormwater in underground structures, the City has purchased the properties at 410 E. Washington and 413 E. Adams. The construction of those structures will allow collection of stormwater affecting another 26 or so residential properties along E. Adams and reduce the amount of stormwater that uses side yard ditches to get the water off the street in that area. Estimated cost for this improvement is $150,000, including a pump to lift the water into a storm main. Because there is no storm main in the area, we will need to construct a new main that will drain the underground collection structures by a combination of gravity and pumping at the 413 E. Adams location. A likely route for the new main is down Adams, then west to Penn where it could head
north to Madison and then discharge into a reach of Engle Creek at a property the City purchased at 204 E. Madison.
The new stormwater main will provide opportunities to collect surface water that makes its way to Engle Creek via side-yard and backyard ditches as well as some front-yard ditches. This main, based on the path it takes, should relieve some of the yard flooding of the neighborhoods in the vicinity. Estimated cost of the main and all its ancillary drain structures is $350,000. An additional 30 residential properties should see the benefits of the new system.
 Now that we have directed stormwater from the 400 and 500 blocks of E. Washington to a reach of Engle Creek, how do we get that water safely beyond the boundaries of O’Fallon? The culvert pipes under E. Wesley Drive between Wesley Pond and Fairwood Lake are old and beginning to rust through. The pipes also appear to be a bit undersized when you consider the increased flow
rate they may see from the new Adams-Penn collector stormwater main described above. The pipes need to be replaced and while performing the replacement work, we should also clean Wesley Pond. The pond is a stilling basin for overland flows of water that originate from not only E. Washington, but as far south as the intersection of State and Lincoln. As water sits in Wesley Pond, particulate matter settles out prior to it getting to Fairwood Lake and then onto a main branch of Engle Creek. Such stilling basins will be invaluable to the City in the future in ensuring that we can meet federal mandates for surface water quality released from our municipal area. To further improve the local environment, an aerator fountain will need to be added to the pond. This work is estimated to cost $180,000, and dramatically impacts six residential properties. It will also provide a visual improvement for every motorist and pedestrian passing by the
pond.
Once the stormwater passes under Wesley, it encounters Fairwood Lake. To slow the water from the E. Washington and State/Lincoln intersection and to reduce its impact on Engle Creek, the dam and overflow structure of the lake needs to be modified. A cursory review of such a modification shows the following impact: by reducing the flow rate flow for the two and ten-year events (storms likely to have a 50% and 10% chance of occurring every year, respectively) by 90%, and for the 100-year event (a chance of 1% every year) the reduction is better than 50%. The dam modification and the work on Wesley Pond will require the permission of the homeowners. The work on the lake’s dam and outlet structure is estimated to cost $110,000, and will take a lot of effort to coordinate
the modification with the Illinois Department of Natural Resources (IDNR).
As you can see, the stormwater drainage issues on E. Washington are intertwined with other stormwater drainage systems in the City. Obtaining the necessary funding for a project of this magnitude is difficult and the execution very complicated. There are numerous issues to consider and many pieces that need to fall into place at the opportune time.
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