Res 2013-163(a)/Approving an agreement w/Halff Assocates for services in connection with the Old Ranch Road 12 bike/ped and widening

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;;; HALFF Page 4 Proposed improvements will be in compliance with TXDOT design criteria. Hydraulic analysis will be conducted to determine the impact of the proposed roadway improvements on driveway and roadway culvert crossings. 2.2.1 Perform field reconnaissance to identify existing site conditions at the proposed drainage crossings. Additional channel surveys may be necessary at the for drainage outfall channels. 2.2.2 Compute the proposed condition peak flow rates for the 2 -, 10-, 25- and 100 -year storm events. 2.2.3 Assuming the majority of the drainage will be open roadside channels, perform hydraulic calculations for the roadside channels to include the depth of flow, the velocity and the shear for the three storm events. HEC -RAS will be used to perform conceptual design modeling for each roadway channel section. After the RAS calculations are concluded that final design will be done within GeoPack. 2.2.4 Evaluate the erosion potential in the roadside channels. Examine the shear and velocity in the channels. Examine grading options to minimize those parameters, as well as the need for permanent turf reinforcement mat (TRM) to resist the erosion. Specific selection of plants or the need for soil amendments or biological inoculation will be made with the COSM staff. 2.2.5 Perform hydraulic calculations for isolated culverts and inlets that may be required at specific street crossings. Calculations will be made for each driveway culvert. 2.3 Design Phase Services (60 %/90% /100 %) 2.3.1 Halff will prepare the roadway design plans for the proposed improvements including the following sheets. All sheets below except cross sections and special details will be included in the 60% submittal. All sheets below will be included in the 90% and 100% submittals. When applicable, a list of quantities for the bid items on a sheet will be included on each sheet. 2.3.1.1 Cover sheet and general note sheet(s) 2.3.1.2 Detailed Index of Sheets 2.3.1.3 Project Layout with survey data and soil boring locations 2.3.1.4 Horizontal Control Sheet(s) 2.3.1.5 Typical Section(s) 2.3.1.6 Quantity and Summary Sheet(s) 2.3.1.7 Traffic Control Details 2.3.1.8 Removal Plans 2.3.1.9 Roadway and Sidewalk Plan/Profile 2.3.1.10 Intersection Details 2.3.1.11 Side Street profiles 2.3.1.12 Pavement Markings and Signing Plan Old RR 12_Design_Option 1