Storm water runoff from areas tributary to the property shall be considered in the design of the property's drainage system.
(A) Upstream area not meeting Code requirements. When areas exist upstream of the property that do not meet the storage and release rates of this Code, regionalized detention on the applicant's property shall be explored by the applicant. The following steps shall be followed:
(1) The applicant shall compute the storage volume needed for his or her property using the release rates prescribed herein, the applicant's property area, and the procedures described herein.
(2) Areas tributary to the applicant's property, not meeting the storage and release rate requirements of this Code, shall be identified.
(3) Using the areas determined above plus the applicant's property area, allowable release rates shall be determined according to the criteria detailed in § 154.24.
(4) Using the areas determined above plus the applicant's property area, and the release rate determined in division (3), above, the total storage needed for the combined properties shall be computed. If tributary areas are not developed, a reasonable fully developed land cover shall be assumed for the purposes of computing storage.
(5) Once the necessary combined storage is computed, the village may choose to pay for over sizing the applicant's detention basin to accommodate the regional flows. The applicant's responsibility will be limited to the storage for his or her property as computed in division (1) above. If regional storage is selected by the village, then the design produced in division (3) above, shall be implemented. If regional storage is rejected by the village, the applicant has the option of bypassing all tributary area flows through or around the applicant's basin according to the procedures detailed in § 154.39. The overflow structure must be designed to accommodate the maximum bypass flows after the required storage has been provided.
(B) Upstream areas meeting Code requirements. When areas exist upstream of the applicant's property that meet the requirements of this Code, the upstream flows shall either be bypassed around, or routed through the applicant's detention basin at the discretion of the village. Storage needed for the applicant's property shall still be computed as described above. However, if the village decides to route tributary area flows through an applicant's basin, the final design storm water releases shall be based on the combined total of the applicant's property plus the tributary area.
(Ord. 801, passed 7-26-05) Penalty, see § 154.99