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Section 5: Documentation and Deliverables

This section provides a general summary of the required documentation for hydraulic analysis and design. The specific documentation requirements for particular types of drainage structures are explained in the chapters dealing with those structures.

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Key Elements of Hydraulic Documentation

The type and nature of documentation and deliverables required varies depending upon the project or effort being undertaken. Whatever the context may be and whatever format of documentation may be used, certain key elements should typically be documented:

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  • Parameter and criteria considerations -- Documentation of parameter and criteria considerations includes data source identification, evaluation of data, assessments of the reliability of data, what decisions were made and why, qualifying statements such as limitations and disclaimers, and design values comprising the set of parameters and criteria that govern the design. Design parameters define the limits of the facility design. For example, in sizing a structure, design parameters include economically available shapes, environmentally suitable materials, and physical geometric limitations. Examples of criteria include allowable headwater (for a culvert), allowable through-bridge velocity (for a bridge), and maximum allowable water discharge rate from a pump station. Both design parameters and criteria are established from the unique characteristics of the design site and situation. The parameter and criteria considerations should be fully documented for the design of TxDOT drainage facilities.
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  • Federal and state regulatory criteria (see Chapter 2).
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  • TxDOT procedures and practices (see Chapter 2).
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  • Past performance of existing facilities at the subject location. Such experience may include operation during flood events, erosion activity, structural response to flood events, failures, maintenance required (and for what reason), and description and cost of maintenance. District offices should develop and maintain systematic documentation files of facility experiences either at the district or at the local level.
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  • Judgments, assumptions and decisions incorporated in the decision process or design.
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  • Plan, profile and detail drawings explaining the design.
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  • Special Provisions, Special Specifications, or General Notes governing material and construction requirements for any element of the drainage design not addressed by standard specifications.
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Special Documentation Requirements for Projects crossing NFIP designated SFHA

A detailed report is required for any bridge replacement or rehabilitation project, or any roadway reconstruction project impacting NFIP floodplains mapped as Zone A (approximate) or Zone AE (detailed study with base flood elevations determined). The TxDOT document “ Recommended Format for Drainage Reports,” describes the expected content of a report in this context. The report typically consists of an introduction, a hydrology description, description of hydraulic analysis and a summary of conclusions and recommendations.

The introduction describes the purpose of the project, the specific impacts on the stream crossing, and the purpose of the study. The hydrology section describes the watershed, including climate, soils, and other pertinent data, and identifies the methodology used to compute flow. The hydraulics section includes analysis of the existing structure or conditions and design alternatives as well as an overview of the hydraulic modeling process. The hydraulics section also discusses design alternatives and provides a preferred alternative.

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Permanent Retention of Documentation

Hydraulic reports and H&H calculations should be retained in the District/Area Office project file for permanent reference. The need for such records may not arise until years after the project has been completed. Retaining these records will provide many benefits, including:

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  • Ease of reference for future alteration or rehabilitation of the subject drainage structure
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  • Justification of design decisions in case of future challenges or litigation
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  • Valuable reference information for the design of other structures crossing the same stream or in the same watershed
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  • Proof of intended compliance with regulations such as NFIP rules
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Documentation Reference Tables

The following tables indicate the required documentation of various facility types for preliminary review, PS&E review, and field change requests. The tables also indicate whether the information should reside in construction plans. The construction plans constitute part of the permanent file, but not all project information resides in the construction plans.

The following table shows the data documentation requirements:

Anchor: #i1016708Table 3-1: Data Documentation Requirements

Documentation Item

(by facility type)

Stage

Location of Information

Data

Preliminary Review

PS&E Review

Field Changes

Construction Plans

Permanent File

Report

Field survey data

X

X

X

 

X

 

Vertical Datum

X

X

X

X

X

X

Historical data

X

X

X

X

X

X

FEMA FIS summary data and maps (where applicable)

X

X

X

 

X

X

Soil maps

X

X

X

 

X

 

Land use maps (when applicable)

X

X

X

X

X

 

Stream gauge data (where applicable)

X

X

X

 

X

X


The following table shows the hydrology documentation requirements:

Anchor: #i1016783Table 3-2: Hydrology Documentation Requirements

Documentation Item

(by facility type)

Stage

Location of Information

Hydrology

Preliminary Review

PS&E Review

Field Changes

Construction Plans

Permanent File

Report

Drainage area map(s) showing boundaries, outfalls, flow paths, etc.

X

X

X

X

X

X

Relevant watershed parameters (e.g. areas, runoff coefficients, slopes, etc.)

X

X

X

X

X

X

Assumptions and limitations

X

X

X

 

X

X

Hydrologic method(s) used

X

X

X

X

X

X

Hydrologic calculations

X

X

X

X

X

X

Peak discharges for design and check floods

X

X

X

X

X

X

Runoff hydrographs for design and check floods (where applicable)

X

X

X

X

X

X


The following table shows the channel documentation requirements:

Anchor: #i1016858Table 3-3: Channel Documentation Requirements

Documentation Item

(by facility type)

Stage

Location of Information

Channels

Preliminary Review

PS&E Review

Field Changes

Construction Plans

Permanent File

Report

See Hydrology for runoff determination

X

X

X

X

X

X

Channel cross sections and thalweg profile

X

X

X

X

X

X

Plan showing location of sections

X

X

X

 

X

X

Cross section subdivisions and "n"-values

X

X

X

X

X

X

Assumptions and limitations

X

X

X

 

X

X

Hydraulic method or program used

X

X

X

X

X

X

Water surface elevations and average velocities for design and check floods

X

X

X

X

X

X

Analysis of existing channel for comparison (if improvements proposed)

X

X

X

X

X

X


The following table shows the culvert documentation requirements:

Anchor: #i1016941Table 3-4: Culvert Documentation Requirements

Documentation Item

(by facility type)

Stage

Location of Information

Culverts

Preliminary Review

PS&E Review

Field Changes

Construction Plans

Permanent File

Report

See Hydrology for discharge data

X

X

X

X

X

X

See Channels for tailwater data

X

X

X

X

X

X

Design criteria (Allowable headwater, outlet velocities, FEMA etc.)

X

X

X

X

X

X

Culvert hydraulic computations

X

X

X

X

X

X

Unconstricted and through-culvert velocities for design and check floods

X

X

X

X

X

X

Calculated headwater for design and check floods

X

X

X

X

X

X

Estimated distance upstream of backwater effect

X

X

X

X

X

X

Magnitude and frequency of overtopping flood

X

X

X

X

X

X


The following table shows the bridge documentation requirements:

Anchor: #i1017024Table 3-5: Bridge Documentation Requirements

Documentation Item

(by facility type)

Stage

Location of Information

Bridges

Preliminary Review

PS&E Review

Field Changes

Construction Plans

Permanent File

Report

See Hydrology for discharge data

X

X

X

X

X

X

See Channels for highwater data

X

X

X

X

X

X

Design criteria/parameters/assumptions (velocities, backwater, FEMA, etc.)

X

X

X

X

X

X

Plan showing location of HEC-RAS cross sections

X

X

X

X

X

X

Bridge hydraulic computations

(cross-section output)

X

X

X

 

 

X

Unconstricted and through-bridge velocities for design and check floods

X

X

X

X

X

X

Calculated maximum backwater for design and check floods

X

X

X

X

X

X

Estimated distance upstream of backwater effect

X

X

X

X

X

X

Magnitude and frequency of overtopping flood

X

X

X

X

X

X

Scour calculations*

X

 

 

 

 

*

Estimated scour envelope*

X

X

X

X

X

*

* Can be combined with the scour computations report required by Bridge Division, Geotechnical Section.



The following table shows the pump station documentation requirements:

Anchor: #i1017131Table 3-6: Pump Station Documentation Requirements

Documentation Item

(by facility type)

Stage

Location of Information

Preliminary Review

PS&E Review

Field Changes

Construction Plans

Permanent File

Report

Pump Stations

 

 

 

 

 

 

See Hydrology for discharge data

X

X

X

X

X

X

See Channels for tailwater data

X

X

X

X

X

X

See Storm Drains for inlet and outlet conduit data

X

X

X

X

X

X

Stage/storage curve

X

X

X

X

 

X

Pump capacity and performance computations

X

X

X

 

X

X

Pump hydraulic performance curves

X

X

X

X

 

X

Design peak and attenuated peak discharges

X

X

X

X

X

X

Maximum allowable headwater elevation

X

X

X

X

X

X

Switch-on and cut-off elevations

X

X

X

X

 

X

Sump dimensions

X

X

X

X

 

 

Head loss calculations and total dynamic head

X

X

X

 

X

X

Pump sizes

X

X

X

X

 

X

Pump station details

 

X

X

X

 

 


The following table shows the storm drain documentation requirements:

Anchor: #i1043207Table 3-7: Storm Drain Documentation Requirements

Documentation Item

(by facility type)

Stage

Location of Information

Storm Drains

Preliminary Review

PS&E Review

Field Changes

Construction Plans

Permanent File

Report

See Hydrology for discharge data

X

X

X

X

X

 

See Channels for tailwater data

X

X

X

X

X

 

Storm drain schematic/layout showing trunklines, laterals, inlets, outfall etc.

X

X

X

X

 

 

Storm drain hydraulic computations including all allowables

X

X

X

X

X

 

Storm drain plan/profile sheets w/ hydraulic grade line

 

X

X

X

X

 

Outfall considerations and information

 

 

 

 

X

 

Flow direction arrows

X

X

X

X

 

 

Evaluation of existing facility (if present)

X

X

 

 

X

 


The following table shows the facility documentation requirements:

Anchor: #i1017363Table 3-8: Other Facility Documentation Requirements

Documentation Item

(by facility type)

Stage

Location of Information

Other Facilities

Preliminary Review

PS&E Review

Field Changes

Construction Plans

Permanent File

Report

Drainage area maps

X

X

X

X

X

X

Design criteria/parameters/assumptions

X

X

X

 

X

X

Hydrologic computations

X

X

X

X

X

X

Hydraulic computations

X

X

X

X

X

X

Plan/profile and details

X

X

X

X

 

X

Design and check flood before and after conditions (highwater, velocities, etc.)

X

X

X

X

X

X


The following table shows the SW3P Layout requirements for projects requiring authorization under the Construction General Permit (TXR150000):

Anchor: #i1017430Table 3-9: SW3P Layout Requirements

Documentation Item

(by facility type)

Stage

Location of Information

SW3P Layouts

Preliminary Review

PS&E Review

Field Changes

Construction Plans

Permanent File

Report

Drainage patterns

X

X

X

X

X

X

Approximate slopes anticipated after major grading activities

X

X

X

X

X

X

Areas that will and will not be disturbed

X

X

X

X

X

X

Locations where storm water will discharge from the project (i.e. discharge points)

X

X

X

X

X

X

Acres of disturbed area that will drain to each discharge point1

X

X

X

X

X

X

Locations of all major BMPs (e.g. silt fence, rock berm, sediment traps, etc.) 2

X

X

X

X

X

X

Areas that will receive temporary or permanent stabilization (e.g. temporary seeding, soil retention blankets, slope texturing, etc.) 3

X

X

X

 

 

X

Locations of surface waters and wetlands on or adjacent to the site (if known)

X

X

X

X

X

X

Names of surface waters that will receive discharge from the project1

X

X

X

X

X

X

1Alternatively, this could be included in the SW3P Summary Sheet

2Structural controls are required at all down slope boundaries, and side slope boundaries as appropriate. Velocity dissipation devices at discharge locations are required if necessary to provide a non-erosive flow velocity from the structure to a watercourse. If it will be necessary to pump or channel standing water from the site, controls to remove sediment from this water are required. BMPs may also be used to divert storm water around disturbed areas.

3Temporary stabilization is required when work in a disturbed area will cease for more than 21 days.



The following table shows the SW3P Summary Sheet requirements for projects requiring authorization under the Construction General Permit (TXR150000):

Anchor: #i1042406Table 3-10: SW3P Summary Sheet Requirements

Documentation Item

(by facility type)

Stage

Location of Information

SW3P Summary Sheet

Preliminary Review

PS&E Review

Field Changes

Construction Plans

Permanent File

Report

If there are more than 10 disturbed acres that drain to a single discharge point, and if it is not possible to install a sediment basin that provides storage for the runoff from a 50%AEP, 24-hour storm per acre drained, a reason why such a basin is not feasible1

X

X

X

X

X

X

A description of the nature of the construction activity

X

X

X

X

X

X

Description of controls to reduce off site tracking of sediment

X

X

X

X

X

X

Description of construction and waste materials expected to be stored on-site and a description of controls to minimize pollutants from these materials.

X

X

X

X

X

X

A list of other potential pollutants and their sources, and description of controls to minimize pollutants from these sources2

X

X

X

X

X

X

Total acreage of the project area

X

X

X

X

X

X

Total acreage of the project area that will be disturbed

X

X

X

 

 

X

Description of the soil or quality of the existing discharge from the site3

X

X

X

X

X

X

A description of the intended schedule or sequence of activities that will disturb soils for major portions of the site. 4

X

X

X

X

X

X

A description of the intended sequence of erosion and sediment control BMP implementation4

X

X

X

X

X

X

A note that the contractor will be responsible for compliance with all applicable environmental laws, rules and regulations for any work not described in the plans.

X

X

X

X

X

X

A note that the contractor is responsible for installing and maintaining BMPs as described in the plans and as directed by TxDOT personnel.

X

 

 

 

 

 

1Acceptable reasons include soils type, slope, available area, public safety, precipitation patterns, site geometry, site vegetation, infiltration capacity, geotechnical factors, depth to groundwater, and other similar considerations.

2Consider if the following may be a potential pollutant: sediment, oil and grease, coolant, pathogens, concrete truck washout, nutrients, etc. Effective controls may include requiring the contractor to maintain equipment free of leaks, develop a spill response plan, cover stored material/chemicals, prohibit concrete wash out in the rain or within a certain distance of waterways, prohibit the storage of materials/chemicals on a paved surface, prohibit application of fertilizer when rain is forecast or in excess of required amounts, etc.

3Consider whether or not preexisting conditions indicate the discharges from the area already contain excessive sediment, or if the site will be unusually vulnerable to erosion during construction.

4The sequences of disturbance and BMP implementation should correspond. For example, “Silt fence and rock berm will be installed prior to initial clearing and grading…after final grading, permanent seeding will be employed.”



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