7.7.9 Drainage Plan Sheets
Refer to the
PS&E Preparation Manual
and the PS&E QC Milestone Checklist for information on specific elements to include on the drainage plan sheets.7.7.9.1 Culvert and Storm Drain Plan Sheets
Culvert and storm drain plan sheets typically include:
- Drainage area maps;
- Hydraulic calculations;
- Culvert layouts (plan and cross section views);
- Special ditch plan and profile sheets (can be shown on roadway P&P sheets);
- Storm drain plan and profile sheets;
- Junction box details;
- Detention/retention facility details; and
- Miscellaneous drainage details (e.g., Special headwall/wingwall details, inlet modifications, outfall details, pipe bedding details, concrete collar details, and RC pipe connections).
Considerations in the preparation of culvert and storm drain layouts and details include:
- Evaluate the need for trench excavation and protection;
- Identify and resolve utility conflicts due to drainage elements;
- Evaluate the need for interim drainage elements due to construction phasing; and
- Coordinate with local agencies if connecting to local agency’s system.
7.7.9.2 Pump Station Plan Sheets
Pump station detail sheets typically include:
- Pump outfall plan and profile sheets;
- Control house details
- Electrical service/motor control center details;
- Control panel details;
- Backup generator details and specifications;
- Wiring diagrams:
- Structural details for pump house wet wells and site plans;
- Pump station details and specifications; and
- Miscellaneous drainage details.
Considerations in the preparation of pump station plan sheets and details include:
- A suitable source of energy for the backup generator (e.g., gasoline, diesel, gas) must be determined;
- The pump station must be located outside the roadway clear zone. In cases where this is not feasible, the pump station must be positioned underground or in a protected area so it does not pose a hazard to motorists;
- Provide space around the facility to allow access for service vehicles and workers; and
- The control house must include electrical outlets and lights for convenient maintenance.
7.7.9.3 Bridge and Bridge-Class Culvert Hydraulic Data Sheets
Each bridge and bridge class culvert must have its own Hydraulic Data Sheet to convey delineated drainage areas, floodplain cross sections used in hydraulic modeling, run-off calculations used, and other elements to document the hydrology and hydraulic design for these structures.
Refer to TxDOT’s
PS&E Preparation Manual
and the PS&E QC Milestone checklist for specific elements to include on the hydraulic data sheets.Considerations in the preparation of hydraulic data sheets include:
- Design improvements in coordination with the roadway design and structural engineers as applicable;
- Contact local FEMA FPA early. The FPA can advise which base model to use and how much, if any, increase in backwater will be allowed. The FPA may also provide a copy of the original model or help locate one. It is advised to work closely with the FPA throughout the project;
- The backwater profile program used in original development of the study may have been one of several types and from one of several sources. In Texas, the model most commonly used is the Hydrologic Engineering Center’s River Analysis System model (HECRAS) from the USACE. Typically, FEMA encourages that the project model be updated to the most current acceptable model. If the stream was originally modeled using HEC-2, subsequent models should be done using HEC-RAS; and
- Floodplain encroachments must be explained in the environmental document.
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