Topographic Base Map. Develop a topographic survey map (1’ contour) of the project area that includes relevant surface features including buildings, property lines, water quality treatment basin sites, drainage channels, curbs, sidewalks, traffic signals, signal induction loops, signs, edge of pavement, power poles, drainage improvements, utility vaults, utility boxes, existing overhead and underground utilities (drainage, sewer, water, telephone, power, cable, natural gas, utility poles, guy wires, fire hydrants, valve boxes, hand-hole boxes, and vaults), fences, walls, and spot elevations, street cross-sections at 25-foot stations with grade shots at grade breaks and vertical offsets extending a minimum of five feet beyond the public right-of-way. Cross-streets will include cross-sections on a minimum of 25-foot intervals for a distance of at least 100 feet beyond the Pioneer Trail right-of-way and extend a minimum of five feet into private property.
Topographic Base Map. We propose to construct a topographic base map that starts with the initial existing topographic mapping discussed above and supplemented with more detailed field surveying in areas where there will likely be proposed prescriptions under the alternatives developed. Features to be captured in the survey will include but not be limited to buildings, property lines, water quality treatment basin sites, drainage channels, curbs, sidewalks, traffic signals, signs, edge of pavement, power poles, drainage improvements, vault boxes and all other infrastructure items listed in the RFP. We also anticipate conducting additional ground survey to define the slopes of culverts and to define the downslope grade line. Task 2 Assumptions:
Topographic Base Map. The topographic survey base map will be prepared for use by the designers in alternatives analysis. This map will be prepared at an accuracy scale of 1 inch = 40 feet with a vertical contour interval of 1 foot. The horizontal datum will be based on the California Coordinate System of 1983, Zone 5 (CCS83) and the vertical datum will be based on North America Vertical Datum of 1988 (NGVD 88) and constrained to Caltrans Survey Control. Obtaining Rights-of-Entry from private property owners (by the City) will be a first order of work to facilitate early mapping for the area. Xxxxxxx Group survey staff will establish semi-permanent primary and secondary control points for the topographic survey based upon the North America Datum of 1983 and the Caltrans High Accuracy Reference Network (XXXX), NAD 83 1991.35 epoch. Prior to the start of field work, Xxxxxxx Group surveyors will coordinate with the City and Caltrans as appropriate to determine the available existing and preferred horizontal control basis. We will set additional control points along the public roads within and near the survey limits so that the project’s survey control will have a high probability of remaining retraceable throughout the project design and construction process. A color orthophoto with a 0.25’ pixel size of the anticipated survey area will be prepared. The aerial photography will be obtained at a scale suitable for preparing topographic mapping at a scale of 1-inch = 40-feet, with a contour interval of 1 foot. Though flown for the specific scale mentioned, mapping will allow for sheets to be prepared using various scales as necessary. Figure 1 shows the area anticipated to be surveyed.
