3505 LOWELL-SNOHOMISH RIVER RD ROTARY PARK 2018-01-02 MF Import

wetlands or wetlands created for mitigation may riot be used for detention of stormwater. Discharge of water to wetlands should mimic natural discharges as much as is feasible. Point source discharges should not be created where they do not naturally occur. Techniques that result in dispersed discharge, such as dispersion trenches or buried perforated pipe located at wetland buffer edges, can be used to mimic naturally occurring sheet flow into wetlands. 16. Per City policies, due to the proximity of the site to environmentally sensitive areas, seasonal limitations will be placed on land alteration activities. Land alteration activities are defined in the City's Design and Construction standards and specifications as clearing, grubbing, excavation, filling, grading, and stockpiling. Determination of the exact seasonal limitation period requires site specific information generally not available until the project design stage. However, preliminary analysis using the information available at this time indicates on the project site will be restricted to the period between April 1 and October 1. 17. if greater than 10,000 square feet of paved surface used by vehicles will be created by this project, water quality enhancement of stormwater runoff from the paved areas must occur prior to discharge of the stormwater from the site or to a stream or wetland. Stormwater detention/retention, quality protection, and enhancement requirements for this project shall be those requirements in effect at the time of application for Public Works permits. Three options for stormwater quality enhancement are presented in the current City Standards. The least preferred option is allowed only if the first two options are infeasible in the opinion of the Public Works Department. The options for stormwater quality enhancement are, in order of preference: 1) An infiltration basin designed and constructed according to City Standards. 2) A wetpond designed and constructed to City Standards. 3) A baffle -type oil/water separator followed by a vegetated swale, both designed and constructed accordin, to City .Standards.