Where authorized by the streets and public utilities committee, an underdrain system may be installed in lieu of the roadside ditch, and shall be constructed in accordance with the following standards unless otherwise approved by the village board of trustees: (Ord., 2-2-2009; amd. 2011 Code)
A. Pipe material shall conform to Illinois department of transportation standard specifications for road and bridge construction, latest edition, for pipe culverts type 1A. The underdrain shall be sized adequately to handle the drainage area to be served and shall be at least equal in diameter to the nearest crossroad culvert serving this drainage area. In no case, however, shall an underdrain of less than fifteen inches (15") in diameter be installed. The minimum pipe slope shall be 0.40 percent. (Ord., 2-2-2009)
B. Each lot shall have, at minimum, an inlet structure on the downstream end of the underdrain. Additional inlet structures shall be required, at the direction of the streets and public utilities committee, when necessary to prevent the obstruction of other drainageways or to prevent ponding. Each inlet structure shall be constructed with an inside dimension of two feet by two feet (2' x 2') square. The inlet structure shall be precast with a frame and grate suitable for use in streets or trafficways (similar to Neenah Foundries no. R3405 or approved equal). The surface of the grate shall be laid flush with the flow line of the new surface drainage swale so as to deposit all surface waters from the adjacent road and lot area into the underdrain system. (Ord., 2-2-2009; amd. 2011 Code)
C. The culvert pipe on the upstream end of the underdrain shall be connected to any existing inlet structure. If no inlet structure exists on the upstream end, the ground at the upstream end shall be sloped from the new surface drainage swale to the existing surface drainage swale with a slope not steeper than three feet (3') horizontal per each vertical foot. The ground on the downstream side of a downstream inlet structure, if no adjoining underdrain exists, shall be similarly sloped. (Ord., 2-2-2009)
D. All areas disturbed in the course of this construction shall be repaired to their original condition, and all waterways shall be hand raked and seeded as directed by the streets and public utilities committee. (Ord., 2-2-2009; amd. 2011 Code)
E. All work and materials used on the village right of way shall be in accordance with the standard specifications for road and bridge construction, latest edition. (Ord., 2-2-2009)