Village staff met recently to document the strategy for addressing outstanding drainage concerns within the Providence Village subdivision. 

BACKGROUND

In 2018, the Village hired an outside consultant to understand the Providence Village drainage issues. Many of the issues were brought up by the residents themselves and most of them pertained to erosion, lack of vegetation growth, and damp yards. The consultant walked through the subdivision to confirm these complaints. The report splits the subdivision into northern and southern halves. The north half is only impacted during high rainfall events (anything that exceeds a 10 year rainfall event) which is expected. The southern half is more impacted during mild rainfall events. This is due to the large drainage area just south of the subdivision. The subdivision was designed to have overland drainage through the rear yards. What intensifies these mild events are the fences, landscape, and/or debris that residents have installed which has narrowed and/or blocked the drainage easements.

Staff reviewed the report and met to discuss possible alternatives to help reduce these issues.

DISCUSSION

The Engineering Division met recently to discuss several key themes which are listed below:

• Rear yard drainage is conveying flows downstream as intended in the original design however there have been consequences undesirable to the residents.Lack of vegetation growth under dense tree canopies or in eroded areas is a concern.
• Several pockets of poor drainage that may be able to be improved
  • Piping the rear yard drainage will only shift the problem downstream and not affect real change or improve conditions.
  • Requiring homeowners to remove obstructions in the drainage easements will be secondary to less invasive modifications where possible.

Improvements proposed to address the above themes:

1. Divert Offsite Drainage:Village staff have met in the field with the offsite property owner to the South.Discussions are currently underway to acquire a drainage easement on their property to construct and maintain a swale along the shared property line with Providence Village.The property owner has deferred to their engineer about possible design options which will then require review and permitting by the Village prior to construction.
2. Storm Sewer Modifications: Localized surcharge of the storm sewer near 410 Cross Rd would be best addressed by modifying geometry of the downstream manhole at Cross Rd and Middle Rd.Storm sewer flow traveling south to north is likely filling the pipe north of Middle Rd because of the pipe configuration and high velocities.Modification to the structure diverting the flow in the proper direction is the least invasive option to address the concern.Currently the Village has received quotes for the work and will be moving forward on a contract.
3. Capturing Roadway Drainage: Majestic Ct has a significant slope to the roadway and residents are concerned with the amount of water that bypasses the storm sewer inlets and overflows between the houses at the end of the cul-du-sac.The best solution to capture the flow while it’s within the street is to add inlets in both the east and west curb line.This layout in storm structures is similar to Calvin Ct which does not experience this drainage concern therefore this is our best option to address this concern.Since Majestic is part of the current pavement patching program for this year, the construction timing is expected in 2019 by a contractor.
4. Maintenance: Storm sewer inspection currently underway as part of the Village’s annual televising contract to identify if there are any pipe defects.If defects are found, the Village will add these locations to the sewer lining program the following year (Summer 2020).

CONCLUSION

Throughout the subdivision rear yard swales function as designed and some homeowner modifications would further improve the situation.  Private modifications could include eliminating any loose debris or permanent structures within the drainage easements such as piles of yard waste, fences, retaining walls, ponds, playgrounds, pools, walking bridges, etc.  Each of these items channelizes the flow causing erosion which creates low spots for water to sit for longer periods of time. 

Overall, the Village Engineering Division feels confident that the combination of items 1 through 4 will address the concerns of residents in a fiscally responsible manner.