A floodplain use permit shall be required for extraction of sand, gravel and other earth products within a floodway or floodplain (which includes the floodway fringe areas) or erosion hazard areas. An engineering study outlining effects on stream mechanics prepared by a state- registered professional civil engineer shall be required with an application for a floodplain use permit for major extraction operations, for operations in locations that appear to be hazardous because of their relative proximity to structures or banks of watercourses, and for any other operations considered by the city engineer to be potentially hazardous. The operations plan and any engineering study required shall meet the approval of the city engineer. For other operations, a study may be required, at the discretion of the city engineer, depending upon the nature of the proposed operation.
The engineering study is for the purpose of evaluating the possible flood- and erosion- related hazards and must include considerations of effects of the excavation on water velocities, direction of flows, volume of flows, channel geometry (shape and size), type of channel banks, depth of flow, and other items that may be pertinent to stream mechanics, which includes an analysis indicating a balanced sediment flow system or channel aggradation, and resultant effects on structures (including but not limited to roads, bridges, culverts and utilities), banks of watercourses, adjoining lands, and groundwater recharge for the respective alluvial watercourse.
Floodplain use permits for sand and gravel mining operations shall be issued for a time limit of one (1) year only. All such permits are subject to review by the city engineer prior to issuance. No mining operation shall be commenced without an approved permit.
In granting the permit, the city engineer may impose restrictions/conditions regarding the location and boundaries of the area where excavations/stockpiles are allowed, the quantity of excavations/stockpiles, and time period and methods of operation.
After July 25, 1990, the effective date of this section, any extraction of sand and gravel or related materials in the floodway, floodway fringe or erosion hazard areas shall be allowed only if a reclamation plan is also provided for the extraction operation. The reclamation plan shall show that all adverse effects of extraction are mitigated. The plan shall also contain a timetable and financial assurances for accomplishing reclamation.
The city engineer may require bonds or other financial assurances appropriate for the sand and gravel extraction operation.
(Ord. No. 7407, ยง 5, 6-25-90)