Hydrologic Studies Sample Clauses
The Hydrologic Studies clause requires the assessment and analysis of water movement, distribution, and quality within a specific area relevant to a project. Typically, this involves conducting surveys, collecting data on rainfall, runoff, and groundwater, and preparing reports that evaluate potential impacts on drainage or flood risk. By mandating these studies, the clause ensures that water-related risks are identified and managed, supporting informed decision-making and compliance with regulatory requirements.
Hydrologic Studies. The Engineer shall provide the following services:
1. Incorporate in the hydrologic study a thorough evaluation of the methodology available, comparison of the results of two or more methods, and calibration of results against measured data, if available.
2. Calculate discharges using appropriate hydrologic methods and as approved by the State.
3. Consider the pre-construction and post-construction conditions in the hydrologic study, as required in the individual Work Authorization.
4. Obtain the drainage area boundaries and hydrologic parameters such as impervious covered areas, and overland flow paths and slopes from appropriate sources including, but are not limited to, topographic maps, GIS modeling, construction plans, and existing hydrologic studies. The Engineer shall not use existing hydrologic studies without assessing of their validity. If necessary, obtain additional information such as local rainfall from official sites such as airports.
5. Include, at a minimum, the “design” frequency to be specified in the Work Authorization and the 1% Annual Exceedance Probability (AEP) storm frequency. The report must include the full range of frequencies (50%, 20% 10%, 4%, 2%, 1%, and 0.2% AEP).
6. Compare calculated discharges to the effective FEMA flows. If calculated discharges are to be used in the model instead of the effective FEMA flows, full justification must be documented.
Hydrologic Studies. The Engineer shall provide the following services: DocuSign Envelope ID: 2136EF24-41E3-476A-9DE8-B6DB65099AD1
a. Incorporate in the hydrologic study a thorough evaluation of the methodology available, comparison of the results of two or more methods, and calibration of results against measured data, if available.
b. Calculate discharges using appropriate hydrologic methods, as included in this document or as approved by the STATE.
c. Consider the pre-construction and post-construction conditions in the hydrologic study, as required in the individual Work Authorization. The additional lanes may be accounted for by increasing percent development or by a higher curve number, as deemed appropriate for the site.
d. Obtain the drainage area boundaries and hydrologic parameters such as impervious covered areas, and overland flow paths and slopes from appropriate sources including, but are not limited to, topographic maps, GIS modeling, construction plans, and existing hydrologic studies. The Engineer shall not use existing hydrologic studies without assessing of their validity. If necessary, obtain additional information such as local rainfall from official sites such as airports.
e. The plan set must include, at a minimum, the “design” frequency to be specified in the Work Authorization and the 1% AEP storm frequency. The report must include the full range of frequencies (50%, 20% 10%, 4%, 2%, 1%, and 0.2% AEP). Perform scour evaluations for both the 100yr and 500yr frequencies.
f. Compare calculated discharges to the effective FEMA flows. If calculated discharges are to be used in the model instead of the effective FEMA flows, full justification must be documented.
Hydrologic Studies. The Engineer shall provide the following services:
161.2.1.1. Incorporate in the hydrologic study a thorough evaluation of the methodology available, comparison of the results of two or more methods, and calibration of results against measured data, if available.
Hydrologic Studies. The Engineer shall provide the following services:
1. Incorporate in the hydrologic study a thorough evaluation of the methodology available, comparison of the results of two or more methods, and calibration of results against measured data, if available.
2. Calculate discharges using appropriate hydrologic methods and as approved by the State.
3. Consider the pre-construction and post-construction conditions in the hydrologic study, as required in the individual Work Authorization.
4. Obtain the drainage area boundaries and hydrologic parameters such as impervious covered areas, and overland flow paths and slopes from appropriate sources including, but are not DocuSign Envelope ID: 8B0EE02C-E455-423C-9476-3FA4EBD98809 limited to, topographic maps, GIS modeling, construction plans, and existing hydrologic studies. The Engineer shall not use existing hydrologic studies without assessing of their validity. If necessary, obtain additional information such as local rainfall from official sites such as airports.
5. Include, at a minimum, the “design” frequency to be specified in the Work Authorization and the 1% Annual Exceedance Probability (AEP) storm frequency. The report must include the full range of frequencies (50%, 20% 10%, 4%, 2%, 1%, and 0.2% AEP).
6. Compare calculated discharges to the effective FEMA flows. If calculated discharges are to be used in the model instead of the effective FEMA flows, full justification must be documented.
Hydrologic Studies. The Engineer shall conduct hydrologic analysis for the limits of project roadway, the contributing drainage area to the roadway and cross drainage structures that includes four outfalls. This analysis shall incorporate a thorough evaluation of the methodology available, comparison of the results of two or more methods, and calibration of results against measured data. The analysis shall consider the pre- construction (existing) and post-construction (proposed) conditions. Specific scope of work includes the following:
1. Delineate existing conditions drainage area boundaries for the approximately 0.79 miles of road- way Right of Way (ROW) and contributing drainage areas to the existing three cross drainage structures. This includes delineation of drainage areas to each crossing / outfall as well as further delineation of sub-drainage areas specific to each existing and proposed ditch / storm sewer. Ex-isting hydrologic studies will not be used without Engineer’s assessment of validity.
2. Determine existing conditions hydrologic parameters such as impervious covered areas, overland flow paths and slopes from appropriate sources including but not limited to topographic maps, GIS modeling, the National Land Cover Dataset (NLCD), and construction plans and existing hydrologic studies. Hydrologic parameters will be calculated for approximately 0.79 miles of existing roadway ROW and contributing drainage area to the three cross drainage structures. This includes the larger drainage areas to each crossing / outfall as well as sub- drainage areas specific to each existing and proposed ditch / storm sewer.
3. Update the available hydrologic studies with Atlas 14 rainfall.
4. Calculate existing conditions discharges using appropriate hydrologic methods. Include at a minimum, the “design” frequency to be specified by the State and the 1% Annual Exceedance Probability (AEP) storm frequency. It may be required to include the full range of frequencies (50%, 20%, 10%, 4%, 2%, 1%, and 0.2% AEP). This includes development of both peak flows and full hydrographs.
5. Delineate proposed conditions drainage area boundaries for the proposed approximately 0.79 miles of roadway ROW and contributing drainage areas to the proposed three cross drainage structures. This includes delineation of drainage areas to each crossing / outfall as well as further delineation of sub-drainage areas specific to each existing and proposed ditch / storm sewer.
6. Determine proposed conditions hydr...
Hydrologic Studies. The Engineer shall provide the following services:
Hydrologic Studies. The Consultant shall provide the following services:
a. Incorporate in the hydrologic study a thorough evaluation of the methodology available, comparison of the results of two or more methods, and calibration of results against measured data.
b. Calculate discharges using appropriate hydrologic methods, as included in this document or as approved by the State.
c. Consider the pre-construction and post-construction conditions in the hydrologic study. The additional lanes must be accounted for by increasing percent development or by a higher curve number, as deemed appropriate for the site.
d. Obtain the drainage area boundaries and hydrologic parameters such as impervious covered areas, and overland flow paths and slopes from appropriate sources such as, topographic maps, GIS modeling, construction plans, and existing hydrologic studies. The Consultant shall not use existing hydrologic studies without assessing of their validity. Obtain additional local rainfall from official sites such as airports.
e. Compare calculated discharges to the effective FEMA flows. If calculated discharges are to be used in the model instead of the effective FEMA flows, full justification must be documented.
Hydrologic Studies. The Engineer shall provide the following services:
1. Incorporate in the hydrologic study a thorough evaluation of the methodology available, comparison of the results of two or more methods, and calibration of results against measured data, if available.
2. Calculate discharges using appropriate hydrologic methods and as approved by the State.
3. Consider the pre-construction and post-construction conditions in the hydrologic study, as required in the individual Work Authorization.
4. Obtain the drainage area boundaries and hydrologic parameters such as impervious covered areas, and overland flow paths and slopes from appropriate sources including, but are not limited to, topographic maps, GIS modeling, construction plans, and existing hydrologic studies. The Engineer shall not use existing hydrologic studies without assessing of their validity. If necessary, obtain additional information such as local rainfall from official sites such as airports. DocuSign Envelope ID: 8F4C5F80-CEA4-4B7A-AA13-EF50310E0F8C
5. Include, at a minimum, the “design” frequency to be specified in the Work Authorization and the 1% Annual Exceedance Probability (AEP) storm frequency. The report must include the full range of frequencies (50%, 20% 10%, 4%, 2%, 1%, and 0.2% AEP).
6. Compare calculated discharges to the effective FEMA flows. If calculated discharges are to be used in the model instead of the effective FEMA flows, full justification must be documented.
Hydrologic Studies. The ENGINEER shall perform a preliminary hydrologic analysis to determine the discharges for the 2-, 10-, 25-, 50-, 100-, and 500-year storm frequency events. Drainage areas delineated under 200 acres shall use the Modified Rational Area Method. Areas greater than 200 acres shall use the Soil Conservation Service (SCS) Curve Number Method or statistical analysis of stream gage data depending on available data as described in the TXDOT 2016 Hydraulic Design Manual. The ENGINEER shall complete the following subtasks: Obtain data. The ENGINEER shall obtain existing Hydrology and Hydraulic models from drainage authorities with purview in the corridor. Other data sources shall include and are not limited to: − FEMA Flood Insurance Studies (FIS) and Flood Insurance Rate Maps (FIRMs) − Latest available terrain surface data and contour maps (from local County or TxDOT) − Land use maps − Soils maps − Historic Precipitation Data − USGS Stream gage data − Aerial imagery (latest available) − Culvert and drainage maintenance reports − Historic Flooding reports − As-built plans and data for impacted hydraulic structures DocuSign Envelope ID: 9E4E3B84-8519-409C-AEF8-0383FB0D2E89 − Design plans (calculations if available) of highway, culverts and ditches Review FIS. The ENGINEER shall review the FEMA Flood Insurance (FIS) and Maps (FIRMs) and compare to the proposed improvements. The ENGINEER shall evaluate the potential impact to the delineated floodplain area Determine Drainage Area Boundaries. The ENGINEER shall determine the existing conditions drainage area boundaries to be used for determining discharges for cross drainage structures, channels, and detention ponds. The delineations shall be based on the available terrain surface data, contour maps, as-built data, and aerial imagery. The ENGINEER shall conduct up to two site visits when needed to identify critical hydrologic and hydraulic areas not visible on maps. Ground survey (to be provided by the STATE) and the latest available terrain surface data and available contour maps along with current aerial imagery shall be used to identify any existing drainage features such as channels, cross drainage structures, roadways, or structures. Complete Hydrologic data/discharge calculation. Time of Concentration calculations will be performed as stated in the TxDOT Hydraulic Design Manual July 2016 edition. Calculated flows shall be compared to FEMA FIS flows and TxDOT’s Regression Analysis Equations. Hydraulic Model...
Hydrologic Studies. The Engineer shall provide the following services:
1. Incorporate in the hydrologic study a thorough evaluation of the methodology available, comparison of the results of two or more methods, and calibration of results against measured data, if available.
2. Calculate discharges using appropriate hydrologic methods and as approved by the State.
3. Consider the pre-construction and post-construction conditions in the hydrologic study, as required in the individual Work Authorization. DocuSign Envelope ID: 211A8780-3A56-4C71-A0A9-95EA90C5E646
4. Obtain the drainage area boundaries and hydrologic parameters such as impervious covered areas, and overland flow paths and slopes from appropriate sources including, but are not limited to, topographic maps, GIS modeling, construction plans, and existing hydrologic studies. The Engineer shall not use existing hydrologic studies without assessing of their validity. If necessary, obtain additional information such as local rainfall from official sites such as airports.
5. Include, at a minimum, the “design” frequency to be specified in the Work Authorization and the 1% Annual Exceedance Probability (AEP) storm frequency. The report must include the full range of frequencies (50%, 20% 10%, 4%, 2%, 1%, and 0.2% AEP).
6. Compare calculated discharges to the effective FEMA flows. If calculated discharges are to be used in the model instead of the effective FEMA flows, full justification must be documented.