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Scope of Services and Schedule <br />Typically, street improvement plans and grading plans are only needed when a property appears to have a <br />private inlet and we need to assess if the storm drain connects directly to the City's storm drain system or <br />to the back of a catch basin. Since WSP has completed the refinement for each catch basin in the City, <br />additional refinement will be needed for redevelopment projects or when additional catch basin or private <br />drop inlets are observed in the field. Under this scope of work, our staff can continue to refine drainage <br />areas based on additional information received or observations. <br />On -Land Visual Trash Assessments (OVTAs) <br />WSP understands the City's goal of <br />meeting the Track 1 compliance. Because <br />of issues such as direct connections and <br />some catch basins identified as infeasible <br />to install FCS, the City has installed CPS <br />in catch basins that were feasible, <br />including both PLU and ALU areas, to <br />meet this Track 1 compliance strategy. <br />The Bay Area Storm Water Management <br />Agencies Association (BASMAA) <br />developed a trash model that correlates <br />different land uses with TGRs for both <br />VISUALTRASH ASSESSMENT SCORING SYSTEM <br />ra .7 <br />A. <br />■ A = clean, no trash (Low trash generation rote) <br />• B = few pieces of trash (Moderate trash generation rate) <br />■ C = small to moderate amounts of trash (High trash generation rote) <br />• D = moderate to high amounts of trash (Very Nigh trash generation rate) <br />PLUs and non-PLU areas and further connects these TGRs with an OVTA score that can be verified <br />through field monitoring. This model will ultimately be used for land substitution under the Track 1 <br />compliance strategy. <br />WSP completed two rounds of OVTA surveys to verify baseline TGRs. Initial OVTA survey results suggest <br />that City land use TGRs are considerably different than BASMAA modeled TGRs. WSP recommends <br />additional rounds of OVTAs under the next contract to further strengthen findings and adjustment of <br />modeled TGRs based on the initial OVTAs. WSP also anticipates the TGR model will need to be verified <br />Trash Generation Rate 9m1q".,..��� .E�.�m. rc�zPnPey1p�Jne1AG5 <br />(gallons/acre/year) ` <br />- 30 -�• fig- 1�. <br />7.5 r •j II <br />2.5 <br />T • <br />' <br />�� <br />� <br />a J 1r7 <br />s`i " <br />- A <br />T <br />.a.. •� <br />Miles i <br />a as i z <br />periodically, requiring additional OVTAs completed. <br />While our initial round of OVTAs were completed <br />using standard two -person field team survey <br />methods, WSP has developed new methods to <br />complete cost-effective trash surveys. WSP's team <br />uses a camera and develops a machine learning <br />algorithm to successfully identify trash and develop <br />corresponding visual trash assessments scores for <br />several survey segments. We anticipate using the <br />machine learning technology for future OVTAs <br />proposed under this contract. <br />Trash Generation Rate Calculations <br />As described above, WSP prepared the initial TGR <br />maps for the City and adjusted the TGRs based on <br />the OVTA findings. WSP assumes TGR maps will <br />be updated based on additional OVTA findings to <br />further strengthen findings and periodic verification will be needed based on the new MS4 permit <br />requirements. After the adjustments are made, WSP will be prepare the TGR calculations. Our extensive <br />City of Santa Ana I Industrial/Commercial Inspection and NPDES Program Support Services I Page 126 <br />RFP No. 23-028 <br />