Road retentions are constructed by replacing a deficit bridge or culvert and replacing it with a smaller sized culvert. The roadway is built up to serve as a temporary dam embankment to store floodwaters during periods of heavy rainfall or snowmelt. The floodwaters are “metered” out over a period of time up to 48 hours. in most situations, road conditions are greatly improved from a safety and road stability standpoint. MNDOT Township Bridge Funds and State Aid Funds can be utilized for these projects as there are typically considerable savings in using smaller diameter culverts to compensate for the cost of additional road fill.