Trinity River Authority of Texas

Ovilla, Ellis County, Texas

G&AI was subcontracted to perform a topographic/design survey of approximately 7,300 linear feet of an existing sanitary sewer line for the purpose of the construction of a new sanitary sewer line adjacent to the existing line. G&AI provided ownership research through Ellis County Appraisal District for approximately 15 parcels of land and prepared permit-to-survey letters and obtained permission from the owners of each affected property to perform necessary surveys. Obtained copies of deeds, subdivision plats and right-of-way maps as required to develop the existing property/right-of-way lines. Established the location of the existing easements and property lines. G&AI establish horizontal and vertical control for the project, and prepared a planimetric detail based on the ground survey showing existing visible elements within 30 feet (minimum) of either side of the existing 30-foot utility easement including, but not limited to the following: (existing pavement, curbs, sidewalks, barrier free ramps, lane striping, driveways, Existing storm sewer inlets, manholes, junction boxes, outfalls, erosion control, culverts, bridges, railroads, guardrail, utility manholes, vaults, water valves, water meters, sprinkler heads, telephone poles, power poles, utility markers, other public utilities, utilities, traffic signal poles, cabinets, other signal equipment, signs (excluding temporary signs), trees, buildings, retaining walls, fence limits and material types, flowlines of creeks, flowlines of manholes, inlets, culverts and other utility structures, property corners, field sketches of manholes and meter stations, and other applicable physical features that could impact design. This phase included cross-sections at 100-foot intervals. G&AI located (horizontally and vertically) 15 bore hole locations for the geotechnical engineer. Deliverables included an AutoCAD drawing file showing all existing features located, including 1-foot contours and tin. Other deliverables included a copy of the field notes, an ASCII point file, property owner list, a copy of the field sketches and a point code list. G&AI also prepared a right-of-way strip map and legal descriptions and exhibits for 11 temporary construction easements, 7 temporary access easements, and 1 temporary construction staging easements and established on the ground the location of the improvements on 50-foot intervals, at all property lines, and at all points of curvature and tangency. G&AI furnished Geographical Information System (“GIS”) data compatible with Esri ArcGIS (.shp file) for each parcel. Subsurface Utility engineering QL “B” was also performed on the project.

Additionally, G&AI was subcontracted to perform a geotechnical investigation for a proposed 7,300 linear feet of sanitary sewer line ranging in diameter from 36 to 42 inches. Various sections of this line are planned for open cut construction; others for thrust bore or tunnel construction. The principal purposes of this investigation were to evaluate the general soil conditions at the proposed site and to develop geotechnical engineering design recommendations. To accomplish this, the study was conducted in the following phases;

1. drill 12 sample borings to evaluate the soil conditions at the boring locations and to obtain soil samples;
2. conduct laboratory tests on selected samples recovered from the borings to establish the pertinent engineering characteristics of the soils; and
3. perform engineering analysis, using field and laboratory data, to develop design criteria. Deliverables included a Geotechnical Engineering Report, which comprised of field boring logs, laboratory data, and engineering analysis.

G&AI consulted with the TRA project team to evaluate geologic subsurface conditions relevant to potential open cut pipeline construction or tunneling through hard rock in a picturesque and residential area.