(a) Except for agricultural purposes, it shall be unlawful for any person to change the drainage pattern of any land by excavating, grading, or filling in any way to change the effect on adjoining property without first obtaining a permit for construction from and where applicable the Township Water and Sewer Department, Building Department, and Department of Public Works. Each site shall receive grading for the purpose of directing surface water run-off to appropriate drainage water systems, and the same shall be done in a manner which will not cause drainage water from the site to flow onto adjacent land or obstruct the flow of existing drainage from adjacent properties. Drainage water systems shall be provided to collect surface water run-off and building foundation drain ground water. The drainage water system shall consist of enclosed storm sewers throughout the project. An extension of the drainage water collection system shall be made to furnish an outlet for foundation drain service pipes for each building having a basement. The collected drainage water shall be conveyed to a point of disposal that shall be a public storm water drain as approved by the appropriate governmental agency.
(b) When, in the opinion of the Township Engineer and/or the office of the Macomb County Commissioner of Public Works, there is inadequate drainage water outlet capacity, the developer shall install a storm sewer of adequate size to serve a logical service area, including his or her site, or obtain a legally signed petition for a special assessment project to install such a storm sewer of adequate size, or construct his or her full share of such a storm sewer of adequate size and provide drainage water storage capacity to limit the rate of flow of drainage water from his or her site to the existing capacity of the outlet. Once approved and constructed, the owner shall not reduce the volume of such drainage water storage facilities on the site without the written approval of the Township. Such drainage water storage capacity which serves a single site may be on the surface of that site's parking lot if the same is properly designed.
Drainage water storage facilities serving more than one site shall be provided by furnishing a retention basin of sufficient capacity and with a controlled outlet to limit the rate of discharge. Final approval of any plans that include a retention basis serving more than one landowner shall be conditioned upon an operation and maintenance agreement with the Township based on the following criteria:
(1) Retention basins on private developments, where ownership will remain consolidated over an extended period of time, such as industrial sites, shopping centers, apartment complexes, etc., should remain in private ownership, subject to Township review as to size, design and proper operation. Maintenance and liability also shall remain with the property owner.
(2) Retention basins serving predominantly single-family areas may be dedicated to the Township for ownership and maintenance, subject to the following criteria and subject to case-by-case review and approval by the Planning Commission and the Township Board.
A. Minimum land area of isolated parcels should be no less than six acres so that they will eventually be usable as public parks. Therefore, adjoining developers should make every effort to consolidate their retention areas into a single site where feasible from the standpoint of engineering. Smaller sites may be acceptable where they abut directly on other Township or elementary, middle or high school sites.
B. Properties shall have a length-to-width ratio of not more than two and one-half to one.
C. Sites for retention basins shall be shown on the preliminary and final plats.
D. Public street access shall be provided directly to the site with a paved roadway.
E. A signed agreement and approved plans shall be in effect prior to Township approval of the final plat. The developer and/or builder shall be responsible for dewatering and maintaining the basin until it is accepted in writing by the Township Board.
F. The developer and/or builder shall make payment to the Township of sufficient funds to cover maintenance, operation and insurance liability costs for a period of fifteen years, and such costs, including a reasonable inflation factor, shall be estimated by the Township Engineer and deposited with the Township prior to construction of the retention basin.
(c) All trunk storm sewers and drains shall conform to the Township's Storm Sewer Master Plan.
(Ord. 281. Passed 10-2-89; Ord. 356. Passed 4-25-05.)