Section 4: Data Evaluation and Documentation
Anchor: #i1000691Data Evaluation Procedure
Experience, knowledge, and judgment are important parts of data evaluation. After collecting data, use the following data evaluation procedure:
- Compile and evaluate data into a usable format. Compile all collected information into a comprehensive and accurate representation of the hydrologic, hydraulic, and physical characteristics of a particular site.
- Determine if the data contain inconsistencies or other unexplained anomalies that might lead to erroneous calculations, assumptions, or conclusions.
- Separate reliable data from unreliable data.
- Combine historical data with data obtained from measurements.
- Evaluate data for consistency, and identify any changes from established patterns.
- Review previous studies, old plans, or prior documentation for data types and sources, information on how the data were used, and indications of accuracy and reliability.
- Carefully evaluate unpublished data for accuracy and reliability.
Review this historical data to determine whether significant changes occurred in the watershed and for usefulness of the data. TxDOT considers valid and accurate any data acquired from publications by established sources, such as the USGS.
Use the procedure to compare data for inconsistencies:
- Evaluate basic data, such as streamflow data derived from non-published sources.
- Summarize this data before use.
- Compare the following data with each other and with the results of the field survey to resolve any inconsistencies: maps, aerial photographs, satellite images, videotapes, and land use studies.
Consult general references to help define the hydrologic character of the site or region under study and aid in the analysis and evaluation of data.
Anchor: #i1000766Data Documentation Items
Begin documenting obtained data as soon as you collect it. In design/analysis documentation, include types and identified sources, actual data items, evaluations, assumptions, and conclusions concerning the data.
Anchor: #i1000776Other Considerations for Drainage Facilities
Consider collecting descriptive data to address the following:
- coordination with other agencies
- compliance with TxDOT policy and administrative guidelines
- consideration of local ordinances and preferences
- careful coordination with affected property owners
Gain a thorough understanding of local, state, and federal requirements regarding the design of roadway drainage facilities.