21.100 HYD Report.pdf

Memo

Date: Tuesday, March 25, 2025

Project: TX FLAP UV CR203(1) Fish Hatchery Road

To: Luis Calderon, CFLHD Hydraulics Steve Sherman, CFLHD, PM

From: Amy Finseth, HDR

Subject: Final Hydraulics Memo

Project Description Improvements are proposed on County Road (CR) 203 (Fish Hatchery Road) for approximately

0.71-miles beginning at the intersection with US 90 and ending at the United States Fish and

Wildlife Service (USFWS) Fish Hatchery entrance. Improvements include rehabilitation of the existing concrete asphalt pavement and widening the roadway from 17-feet to a width of 24-feet and associated drainage improvements.

Culvert extensions will be needed at both existing culvert crossings. The drainage work included in the scope provided in this memo will document the existing conditions of the two existing cross culverts and recommendations for replacement.

Design Criteria Criteria follows the Federal Highway Administration (FHWA) Project Development and Design

Manual (PDDM) based on a low-standard road classification

Table 1 H&H Criteria Summary

Design Feature PDDM Criteria

Hydrology

Peak Flow Method Rational Method – up to 200 acres (HDS 2)

USGS Regression Equations USGS Regression Equation –Watersheds greater than 200 acres (HDS 2) Culverts

Capacity Design and Stability Design: Cross culverts: 25-year; Parallel Culverts: 10-year

Allowable Headwater

New culverts: ≤ bottom of the roadway aggregate base layer

Existing: less than the shoulder hinge point

HW/D ratio: 48-inches or smaller, 1.5

WSEL limited by unacceptable hazards to human life or property

CFLHD | TX FLAP UV CR203(1)

Hydraulics Memo hdrinc.com 1670 Broadway, Suite 3400, Denver, CO 80202-4824

(303) 764-1520

Design Feature PDDM Criteria

Minimum Size Cross-road culvert : 24” or equivalent

Parallel culvert : 18" or equivalent

Pipe Material

Minimum pipe classification

RCP: Class II, Metal 0.064"

50-year service life

Minimum and

Maximum Outlet Velocity

Minimum : 3 fps

Maximum : as determined by HEC22; matching existing channel velocities.

Outlet Protection Riprap aprons (HEC 14)

Hydrology

Drainage basins were delineated using existing terrain data from United Stations Geological

Survey (USGS), arial imagery, and local survey. Methods for developing hydrology followed

Hydraulic Design Series (HDS) 2 Highway Hydrology and local Texas Department of

Transportation (TxDOT) Design Manual recommendations. Three methods were used: the rational method (up to 200 acres), the USGS Regression Equation (for rural watersheds) and

TR-55 SCS method.

This project has two subbasins larger than 200 acres, therefore the rational method is not applicable for use in these basins. The TxDOT Drainage Design Manual recommends rational method for small drainage areas. Regression equations are recommended as the primary hydrologic method for off-system (non-TxDOT ) projects for areas greater than one square mile.

Win TR-55 software was used to develop the SCS method. Results of the SCS method is not listed in the local DOT criteria and was significantly greater than that found using the rational method and will not be used for design but is included for reference.

For the purpose of this analysis all subbasins do not require flow determined. One basin less than two acres contributes to one culvert within the project (B4) and will use the rational method.

All other basins B1 through B7 totaling over one square mile contribute to the second culvert within the project and will use the regression equations.

Regression equations were developed for natural basins in Texas. Equations are provided in the TxDOT Hydraulic Design Manual (09/2019) Chapter 4 Table 4-4 and were used to develop peak runoff. Natural basins are defined as having less than 10% impervious cover, less than

10% of its drainage area controlled by reservoirs, and no other human-related factors affecting streamflow. The manual recommends this method for drainage areas greater than one square mile (sq mi). The analysis used the sum of all subbasin areas totaling 1,121 acres or 1.8 square miles. Equations from the TxDOT HDM are:

Q25 P 1.140 S 0.446 x 10 [0.945 Ω + 11.79 - 9.819A -0.0374 ]

Q100 P 1.071 S 0.507 x 10 [0.969 Ω + 10.82 - 8.44A -0.0467 ]

Where A is the contributing area in square miles, P is mean annual average precipitation in inches, Omega EM is a generalized terrain and climate index.

Results of the three hydrologic methods are summarized in Table 2 where B4 represents culvert

48+33, and Design Point (DP) 5 represents culvert 24+84.

A drainage area map is attached that identifies routing of the offsite basins, contributing areas and characteristics and the previously mentioned design points (DP).

Table 2 Hydrologic Analysis

Contributing

Area ID Basin Location

Area

(acres)

Rational

Method

Q25 (cfs)

SCS / TR-55

Q25 (cfs)

USGS Regression

Equation

Q25 (cfs)

B1 North of US Hwy 90 235 - 527 -

B2 North of US Hwy 90 83 84 184 -

B3 North of US Hwy 90 53 75 222 -

B4 Culvert 48+33 1.6 *4 15 -

B5 South of US Hwy 90 74 50 230 -

B6 South of US Hwy 90 89 92 421 -

B7 South of US Hwy 90 589 - 2,117 -

DP5 Culvert 24+84 1,122 - 3,218 *1,025 *Flows used for the hydraulic analysis.

The topography is flat with wide heavily vegetated areas contributing to the culverts along CR

203. Offsite contributing areas drain from the north under Highway 90 and from the west. The area contributing to culvert 48+33 includes primarily vegetated cover with some small structures. The area contributing to culvert 24+84 drains through primarily shallow tilled, row crop agricultural fields, vegetated swales, and some areas of steeper brush covered and untilled.

Rainfall depth and intensity was collected from the National Oceanic and Atmospheric

Administration (NOAA) Precipitation Frequency Data Server (PFDS). The annual precipitation depth is provided in Figure 4-6 of the TxDOT HDM.

Hydrology was developed for the 25-year and 100-year peak runoff. The rational method was used for basin, B4, that drains to culvert 48+33. The design flow of 4 cfs was used for the existing and proposed condition. The regression equation was used for DP5, culvert 24+84. The design flow for this culvert is 1,025 cfs.

Hydraulics

There are two culverts that cross CR 203 within the limits of the Project. HY8 was used to evaluate culvert capacity in existing and proposed conditions. The allowable HW/D for both culverts is 1.5.

Culvert 48+33 has a small contributing area, and the hydraulic analysis shows that the existing culvert meets current design standards. However, the existing culvert has deteriorated and would need to be extended with the proposed roadway improvements. Therefore, this culvert will be replaced with a 24-inch equivalent culvert to attain minimum cover.

Results of the hydraulic analysis show the existing 30-inch culvert at 24+84 does not meet current design standards. The analysis for this culvert was updated to reflect additional information obtained after the 30% design. Additional offsite contours and imagery from GIS indicate that the contributing area extends further to the north and west. Runoff is routed through several subbasins in roadside ditches, culverts and large tilled agricultural fields. The resultant design peak flow is over 1,000 cfs at this location. This volume cannot be conveyed by a 30 or 36-inch or dual culverts. The existing finished grade does not provide adequate cover to increase the existing culvert diameter.

The Refuge had expressed interest in adding a second barrel at this location, although no flooding issues had been reported. With the resultant peak flow rate of 1,025 cfs but no reported flooding or overtopping of the road leads to a few assumptions. A more detailed drainage study may be needed to verify contributing areas, or runoff could be inadvertently detained throughout the watershed within the flat terrain averaging 0.5% before or without reaching the culvert.

The roadway profile will be raised and will provide cover to increase this culvert to a 36-inch diameter culvert. However, this diameter does not meet hydraulic criteria. Working within the scope of work and site constraints of the Project, a larger diameter culvert is proposed that will improve conveyance. A culvert that can convey a 25-year design flow of 1,025 cfs would require significant site adjustment that is not feasible and cost of infrastructure that is outside the scope of this project. The hydraulic results are summarized in Table 3.

Table 3 Culvert Analysis

Culvert ID, Station

Q25

(cfs)

Culvert

Diameter

(inches) Material

Edge of

Pavement

Elevation

(feet)

Headwater

Elevation

(feet)

HW/D

Existing

48+33 4 24 CMP 922.06 919.87 0.6

Proposed

48+33 4 30 x 19 RCP 922.75 919.69 0.6

Existing

24+84 1,025 30 CMP 914.75 917.68 2.8

Proposed

24+84 1,025 36 RCP 916.70 918.95 2.8

FHWA Standard C251-50 for placed riprap at culvert outlets will be used for outlet protection.

The roadway profile raise introduces roadside ditches. Due to the topography constraints the geometry of the ditches are limited. The ditches were not designed to convey a determined design frequency but are intended to allow water out of and away from the aggregate base. The ditches are trapezoidal with a 4-foot bottom and 1:6 foreslope and 1:4 backslope with 8-inches below the bottom of the aggregate base. This maximizes the depth available for ditches to daylight. Ditches intersect existing driveways or access drives at five locations and do not have existing side drains. However, the Refuge does not want to add new culverts at these locations.

The flat terrain along and surrounding CR 203 currently has pockets of areas with shallow ponding. Along CR 203 most of these locations are at existing driveways or pullouts. The driveways do not have sufficient depth above the ditch flowline to add a side drain. The existing condition at the intersection of the driveways results in shallow ponding, or in larger storm events may pond before overtopping the driveway and draining into the downstream ditch.

Offsite areas along the road can contribute larger drainage areas to the roadside ditch than the roadway itself. The terrain model was optimized to the extent possible while staying within the

ROW and working within the constraints of the flat topography. The existing conditions are maintained or improved by widening the bottom of the ditch with a cross slope draining away from the road or forcing the back slope to provide an outlet away from the road.

An example of an intersection with a driveway at station 34+50 left, the tie in of the backslope is lower than the bottom of the subgrade to promote positive drainage away from the road.

An example of a location that is not at a driveway is shown at station 27+50 right. Ditches drain from north and south to this point. The backslope of the ditch is lower than the elevation at the bottom of the subgrade to promote runoff away from the road.

Summary

In summary the two existing culverts along the project will be replaced, the roadway profile will be raised to accommodate an improved roadway section which also provides clearance to increase one pipe size at station 48+33. Proposed ditches will act primarily to allow water out of the aggregate base. Grading along the roadway was improved as much as feasible within the constraints of shallow terrain and surrounding landscape. Existing drainage patterns are maintained with the proposed roadway improvements.

References

1. Federal Highway Administration (FHWA) Project Development and Design Manual

(PDDM).

2. Federal Highway Administration. 2024. Highway Hydrology. Second Edition. Hydraulic

Design Series No. 2.

3. Federal Highway Administration. 2006. Hydraulic Design of Energy Dissipators for

Culverts and Channels. Third Edition. Hydraulic Engineering Circular No. 14.

4. Federal Highway Administration. 2024. Urban Drainage Design Manual. Fourth Edition.

Hydrau1025lic Engineering Cicular No. 22.

5. National Oceanic and Atmospheric Administration, Precipitation Frequency Data Server, September 10, 2024.

6. National Resources Conservation Service, Web Soil Survey, Hydrologic Soil Data, September 10, 2024.

7. Texas Department of Transportation. Hydraulic Design Manual. 2019.

9409 40

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0 500 1,000

US FEET

UVALDE

COUNTY ROAD 203

DRAINAGE AREA MAP

Existing Culvert

Basin Boundary

Project Alignment

Esri, CGIAR, USGS, Texas Parks & Wildlife, CONANP, Esri, TomTom, Garmin, Foursquare, SafeGraph, FAO, METI/NASA, USGS, EPA, NPS, USFWS, Maxar

PATH: X:\PROJECTS\CENTRAL_FEDERAL_LANDS\10370075_CFLHD_TO53N_TX_FLAP_UV_CR203\7.2_WIP\APRX\TX_FLAP_UV_CR203.APRX - USER: CBURLISON - DATE: 1/8/2025

SOURCE:

insert client logo

D

B

B1

B3 B2

B4

B5

B7

B6

DD

DP

ID Acres CFS B1 235 527

B2 84 184

B3 53 222

B4 2 4

B5 74 230

B6 89 421

B7 589 2117

DP5 1122 1025

DP1

DP2 DP3

DP4

DP5

CULVERT 24+84

CR 203(1)

CULVERT 48+33

FISH HATCHERY ENTRANCE

US HWY 90

Basin

ID

Area (acres)

Q25 (cfs)

Direction of Flow

Drainage Area ID

Design Point

Uvalde

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12234

Hydrologic Soil Group—Uvalde County, Texas (Fish Hatchery Road)

Natural Resources Conservation Service

Web Soil Survey National Cooperative Soil Survey

9/10/2024

414700 415300 415900 416500 417100 417700 418300 418900 419500 420100 420700

414700 415300 415900 416500 417100 417700 418300 418900 419500 420100 420700

29° 12' 42'' N

2'

4' ' W

29° 12' 42'' N

8'

0' ' W

29° 10' 29'' N

2'

4' ' W

29° 10' 29'' N

8'

0' ' W

N

Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 14N WGS84 0 1000 2000 4000 6000

Feet 0 400 800 1600 2400

Meters Map Scale: 1:28,900 if printed on A landscape (11" x 8.5") sheet.

Project

MAP LEGEND MAP INFORMATION

Area of Interest (AOI) Area of Interest (AOI)

Soils Soil Rating Polygons

A

A/D

B

B/D

C

C/D

D

Not rated or not available

Soil Rating Lines A

A/D

B

B/D

C

C/D

D

Not rated or not available

Soil Rating Points A

A/D

B

B/D

C

C/D

D

Not rated or not available

Water Features Streams and Canals

Transportation Rails

Interstate Highways

US Routes

Major Roads

Local Roads

Background Aerial Photography

The soil surveys that comprise your AOI were mapped at 1:24,000.

Please rely on the bar scale on each map sheet for map measurements.

Source of Map: Natural Resources Conservation Service Web Soil Survey URL:

Coordinate System: Web Mercator (EPSG:3857)

Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required.

This product is generated from the USDA-NRCS certified data as of the version date(s) listed below.

Soil Survey Area: Uvalde County, Texas Survey Area Data: Version 21, Sep 5, 2023

Soil map units are labeled (as space allows) for map scales 1:50,000 or larger.

Date(s) aerial images were photographed: Mar 18, 2021—Mar 26, 2021

The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident.

Hydrologic Soil Group—Uvalde County, Texas (Fish Hatchery Road)

Natural Resources Conservation Service

Web Soil Survey National Cooperative Soil Survey

9/10/2024

Hydrologic Soil Group

Map unit symbol Map unit name Rating Acres in AOI Percent of AOI

InD Ingram stony soils, hilly D 16.6 0.8%

KnA Knippa clay, 0 to 1 percent slopes

C 14.4 0.7%

KnB Knippa clay, 1 to 3 percent slopes

C 9.7 0.5%

Me Montell clay D 9.7 0.5%

MoA Montell clay, 0 to 1 percent slopes

D 1,007.1 48.8%

MoB Montell clay, 1 to 3 percent slopes

D 0.8 0.0%

OLB Olmos very cobbly loam, 1 to 8 percent slopes

D 47.7 2.3%

OMB Olmos and Langtry soils undifferentiated, 1 to 8 percent slopes

D 307.6 14.9%

ToA Tobosa clay, 0 to 1 percent slopes

D 6.1 0.3%

UvA Uvalde clay loam, 0 to 1 percent slopes

C 576.6 27.9%

UvB Uvalde clay loam, 1 to 3 percent slopes

C 25.9 1.3%

VaB Valco clay loam, 0 to 3 percent slopes

D 30.7 1.5%

W Water D 11.6 0.6%

Totals for Area of Interest 2,064.5 100.0%

Hydrologic Soil Group—Uvalde County, Texas Fish Hatchery Road

Natural Resources Conservation Service

Web Soil Survey National Cooperative Soil Survey

Description

Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long-duration storms.

The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (A/D, B/D, and C/D). The groups are defined as follows:

Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission.

Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture.

These soils have a moderate rate of water transmission.

Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission.

Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission.

If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes.

Rating Options

Aggregation Method: Dominant Condition

Component Percent Cutoff: None Specified

Tie-break Rule: Higher

Hydrologic Soil Group—Uvalde County, Texas Fish Hatchery Road

Natural Resources Conservation Service

Web Soil Survey National Cooperative Soil Survey

93°94°95°96°97°98°99°100°101°102°103°104°105°106°107°

36°

35°

34°

33°

32°

31°

30°

29°

28°

27°

26°

−0.232

−0.232−0.232−0.232

−0.070−0.232−0.232

−0.384 0.0040.1690.197−0.273−0.413

0.3510.3860.286−0.398−0.398 −0.134−0.1670.1400.1470.1920.330

0.2110.1750.157−0.503 −0.102

−0.503 −0.102 −0.309−0.2530.0710.0130.1250.1120.345

−0.0010.0250.025−0.146−0.200−0.102−0.102 −0.159−0.120−0.1270.2580.161−0.1060.071

−0.076−0.104−0.153−0.242−0.212 −0.294−0.230−0.0150.1210.175−0.058−0.166

−0.083−0.103−0.091−0.144−0.103 −0.1520.0030.1520.2360.0610.015−0.005

−0.063−0.157−0.141−0.207−0.138 −0.0370.0420.1230.1380.1230.058−0.027

−0.006−0.060−0.083−0.089−0.077 0.018

−0.054−0.159−0.125−0.127−0.138 −0.042

125 250 MILES

200 400 KILOMETERS

Base from Texas Natural Resources Information System digital data Scale 1:7,920,000 Albers equal-area projection, datum NAD 83 Standard parallels 27°30' and 35°00', latitude of origin 31°00', central meridian -100°00' Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83).

Uvalde County

Uvalde County

Designer:

Company: 2-yr 5-yr 10-yr 25-yr 50-yr 100-yr 500-yr

Date: 1-hour rainfall depth, P1 (in) = 1.93 2.46 2.91 3.54 4.02 4.52

Project: a b c

Location: Rainfall Intensity Equation Coefficients = 28.50 10.00 0.786

2-yr 5-yr 10-yr 25-yr 50-yr 100-yr 500-yr

Overland

Flow Length

Li (ft)

U/S Elevation

(ft)

(Optional)

D/S Elevation

(ft)

(Optional)

Overland

Flow Slope

Si (ft/ft)

Overland

Flow Time ti (min)

Channelized

Flow Length

Lt (ft)

U/S Elevation

(ft)

(Optional)

D/S Elevation

(ft)

(Optional)

Channelized

Flow Slope

St (ft/ft)

NRCS

Conveyance

Factor K

Channelized

Flow

Velocity

Vt (ft/sec)

Channelized

Flow Time tt (min)

Computed tc (min)

Regional tc (min)

Selected tc (min) 2-yr 5-yr 10-yr 25-yr 50-yr 100-yr 500-yr 2-yr 5-yr 10-yr 25-yr 50-yr 100-yr 500-yr

0.01 0.05 0.15 0.33 0.40 0.49 0.59 21.10 76.89 76.89 1.65 2.10 2.48 3.02 3.43 3.85 1.41 8.93 30.21 82.73 114.63 157.46

0.01 0.05 0.15 0.33 0.40 0.49 0.59 16.19 44.73 44.73 2.37 3.02 3.57 4.34 4.93 5.54 1.27 8.05 27.22 74.54 103.27 141.86

0.01 0.05 0.15 0.33 0.40 0.49 0.59 13.37 17.20 17.20 4.10 5.23 6.18 7.52 8.54 9.60 0.07 0.43 1.45 3.97 5.51 7.56

0.01 0.05 0.15 0.33 0.40 0.49 0.59 26.06 223.17 131.86 1.12 1.43 1.69 2.05 2.33 2.62 0.85 5.34 18.08 49.50 68.58 94.20

0.01 0.05 0.15 0.33 0.40 0.49 0.59 23.06 109.18 72.06 1.72 2.19 2.60 3.16 3.59 4.03 1.57 9.91 33.51 91.75 127.12 174.62

C 2.0

Rainfall Intensity, I (in/hr) Peak Flow, Q (cfs)

Calculation of Peak Runoff using Rational Method

Overland (Initial) Flow Time Channelized (Travel) Flow Time Time of ConcentrationRunoff Coefficient, C

Subcatchment

Name

Area

(ac)

NRCS

Hydrologic

Soil Group

Percent

Imperviousness

Select UDFCD location for NOAA Atlas 14 Rainfall Depths from the pulldown list OR enter your own depths obtained from the NOAA website (click this link)

Cells of this color are for required user-input

Cells of this color are for optional override values

Cells of this color are for calculated results based on overrides

CB

HDR

1/8/2025

UVAL

Uvalde, TX

Version 2.00 released May 2017

15 1.90 3.83

115.83

B3 52.00 C 2.0 98.00 0.016 3209.00 0.016 15 1.87 28.55

0.003 15 0.82 55.79100.00 0.007 2750.00B2 83.00

131.86

31.85

B5 73.00 C 2.0 100.00 0.004 3740.00 0.004 5 0.32 197.12

71.80

B4 1.60 C 2.0 68.00 0.016 436.00 0.016

72.060.006 5 0.37 86.120.006 1916.00B6 88.00 C 2.0 100.00

I ��/ℎ� � a ∗ P� b t� t� �

0.395 1.1 � C� L�

S� t� � L�

60K S�

L�

60V�

Computed t� � t� t�

Regional t� � 26 � 17i

L�

60 14i 9 S�

Selected t� � max t3�4�353 , min Computed t� , Regional t� t3�4�353� 5 (urban) t3�4�353� 10 (non-urban)

Q 89: � CIA

Project: CFLHD TX FLAP Uvalde CR203 Computed: CMB Date: 8/27/2024

Job #: 10370075 Checked: AF Date: 9/9/2024

Page: 1 of 3

* Minimum precipitation value

Contributing Areas

ID Area acres

Table 4-4 B1 235

Regression Equations for Natural Basins B2 83

Design Storm, 25 year B3 52

Q25 P 1.140

S 0.446 x 10 [0.945 Ω + 11.79 - 9.819A -0.0374 ]

B4 1.6

Q100 P 1.071

S 0.507 x 10 [0.969 Ω + 10.82 - 8.44A -0.0467 ]

B5 73

B6 88

Where: B7 588

QT peak discharge of recurrence interval / years (cfs) Total 1,121

P mean annual precipitation in inches from Figure 4-6

S dimensionless main channel slope

Ω OmegaEM from Figure 4-5

A contributing drainage area (mi

QT ,100-Year Peak Discharge (cfs) 1,554

Regression Equation

A, Contributing drainage Area (square miles) 1.8

P, Mean Annual Average Precipitation (inches) * 25

QT ,25-Year Peak Discharge (cfs) 1,025

0.004Dimensionless Main Channel Slope

Omega EM (Ω ) 0.33

Project: TX FLAP Uvalde CR203 Page: 2 of: 3

Figure 4-6. Mean annual precipitation, in inches

Project Location

Project: TX FLAP Uvalde CR203 Page: 3 of: 3

Figure 4-5.

OmegaEM (Ω) quadrangles for Texas regression equations

Project Location

WinTR-55 Current Data Description

--- Identification Data ---

User: cburlison Date: 9/30/2024

Project: CFLHD-Uval Units: English

SubTitle: TX_FLAP_UV_CR203 Areal Units: Acres

State: Texas

County: Uvalde

Filename: C:\Users\afinseth\Desktop\UVAL.w55

--- Sub-Area Data ---

Name Description Reach Area(ac) RCN Tc

B3 offsite east R5 52.06 83 .725

B7 Large Basin to 24+84 R6 588.33 87 1.008

B5 N Subbasin 25+84 L R6 73.42 88 1.251

B6 S Subbasin 25+84L Outlet 88.19 87 .669

B1 Offsite 25+84_Large R7 235.25 87 1.929

B2 Offsite West R3 83.33 67 1.106

B4 Offsite East R5 1.61 85 .146

Total area: 1122.19 (ac)

--- Storm Data --

Rainfall Depth by Rainfall Return Period

2-Yr 5-Yr 10-Yr 25-Yr 50-Yr 100-Yr -Yr

(in) (in) (in) (in) (in) (in) (in)

3.76 5.05 6.3 8.23 9.91 11.9 .0

Storm Data Source: User-provided custom storm data

Rainfall Distribution Type: Type II

Dimensionless Unit Hydrograph: <standard>

WinTR-55, Version 1.00.10 Page 1 12/23/2024 4:40:16 PM

SCS Method Analysis (For Information) cburlison CFLHD-Uval

TX_FLAP_UV_CR203

Uvalde County, Texas

Sub-Area Summary Table

Sub-Area Drainage Time of Curve Receiving Sub-Area

Identifier Area Concentration Number Reach Description

(ac) (hr)

B3 52.06 0.725 83 R5 offsite east

B7 588.33 1.008 87 R6 Large Basin to 24+84

B5 73.42 1.251 88 R6 N Subbasin 25+84 L

B6 88.19 0.669 87 Outlet S Subbasin 25+84L

B1 235.25 1.929 87 R7 Offsite 25+84_Large

B2 83.33 1.106 67 R3 Offsite West

B4 1.61 0.146 85 R5 Offsite East

Total Area: 1122.19 (ac)

WinTR-55, Version 1.00.10 Page 1 12/23/2024 4:40:16 PM

Uvalde County, Texas

Sub-Area Time of Concentration Details

Sub-Area Flow Mannings's End Wetted Travel

Identifier/ Length Slope n Area Perimeter Velocity Time

(ft) (ft/ft) (sq ft) (ft) (ft/sec) (hr)

B3

SHEET 98 0.0051 0.170 0.283

SHALLOW 3209 0.0156 0.050 0.442

Time of Concentration .725

B7

SHEET 90 0.0330 0.170 0.125

SHALLOW 9362 0.0333 0.050 0.883

Time of Concentration 1.008

B5

SHEET 100 0.0092 0.150 0.206

SHALLOW 3740 0.0038 0.050 1.045

Time of Concentration 1.251

B6

SHEET 100 0.0074 0.150 0.224

SHALLOW 1916 0.0055 0.050 0.445

Time of Concentration .669

B1

SHEET 100 0.0960 0.150 0.080

SHALLOW 7206 0.0045 0.050 1.849

Time of Concentration 1.929

B2

SHEET 100 0.0072 0.150 0.227

SHALLOW 2750 0.0029 0.050 0.879

Time of Concentration 1.106

B4

SHEET 68 0.0367 0.150 0.087

SHALLOW 436 0.0161 0.050 0.059

Time of Concentration .146

Uvalde County, Texas

Sub-Area Land Use and Curve Number Details

Sub-Area Hydrologic Sub-Area Curve

Identifier Land Use Soil Area Number

Group (ac)

B3 Desert shrub (good) C 15.618 79

Desert shrub (good) D 36.442 84

Total Area / Weighted Curve Number 52.06 83

B7 Row Crop Straight row [SR] (good) C 294.165 85

Row Crop Straight row [SR] (good) D 294.165 89

Total Area / Weighted Curve Number 588.33 87

B5 Fallow Crop residue [CR] (good) C 66.078 88

Fallow Crop residue [CR] (good) D 7.342 90

Total Area / Weighted Curve Number 73.42 88

B6 Row Crop Straight row [SR] (good) C 44.095 85

Row Crop Straight row [SR] (good) D 44.095 89

Total Area / Weighted Curve Number 88.19 87

B1 Row Crop Straight row [SR] (good) C 117.625 85

Row Crop Straight row [SR] (good) D 117.625 89

Total Area / Weighted Curve Number 235.25 87

B2 Brush - brush, weed, grass mix (good) C 62.498 65

Brush - brush, weed, grass mix (good) D 20.833 73

Total Area / Weighted Curve Number 83.33 67

B4 Farmsteads C .483 82

Farmsteads D 1.127 86

Total Area / Weighted Curve Number 1.61 85

Uvalde County, Texas

Reach Channel Rating Details

Reach Reach Reach Friction Bottom Side

Identifier Length Manning's Slope Width Slope

(ft) n (ft/ft) (ft)

R7 3735 0.03 0.0043 2 5 :1

R6 1439 0.03 0.0014 2 5 :1

R5 1713 0.03 0.0035 2 5 :1

R3 500 0.03 0.004 2 5 :1

Reach End Top Friction

Identifier Stage Flow Area Width Slope

(ft) (cfs) (sq ft) (ft) (ft/ft)

R7 0.0 0.000 0 2 0.0043

0.5 3.397 2.3 7

1.0 15.701 7 12

2.0 81.634 24 22

5.0 817.946 135 52

10.0 4939.349 520 102

20.0 30560.401 2040 202

R6 0.0 0.000 0 2 0.0014

0.5 1.939 2.3 7

1.0 8.959 7 12

2.0 46.580 24 22

5.0 466.718 135 52

10.0 2818.380 520 102

20.0 17437.685 2040 202

R5 0.0 0.000 0 2 0.0035

0.5 3.065 2.3 7

1.0 14.166 7 12

2.0 73.649 24 22

5.0 737.945 135 52

10.0 4456.250 520 102

20.0 27571.401 2040 202

R3 0.0 0.000 0 2 0.004

0.5 3.277 2.3 7

1.0 15.144 7 12

2.0 78.734 24 22

5.0 788.897 135 52

10.0 4763.931 520 102

20.0 29475.068 2040 202

Hydraulics

HY-8 Culvert Analysis Report : 24+84 Existing

Crossing Discharge Data Discharge Selection Method: Recurrence

Table 1 - Summary of Culvert Flows at Crossing: 24+84 Existing

Headwater

Elevation (ft)

Discharge

Names

Total

Discharge

(cfs)

Culvert 1

Discharge

(cfs)

Roadway

Discharge

(cfs)

Iterations

917.70 25 year 1025.00 32.63 992.36 6

918.41 100 year 1554.00 30.24 1523.74 3

915.50 Overtopping 37.76 37.76 0.00 Overtopping

Culvert Data: 24+84 Existing

Table 1 - Culvert Summary Table: Culvert 1

Discharge

Names

Total

Discharge

(cfs)

Culvert

Discharge

(cfs)

Headwater

Elevation

(ft)

Inlet

Control

Depth

(ft)

Outlet

Control

Depth

(ft)

Flow

Type

Normal

Depth

(ft)

Critical

Depth

(ft)

Outlet

Depth

(ft)

Tailwater

Depth

(ft)

Outlet

Velocity

(ft/s)

Tailwater

Velocity

(ft/s)

25 year 1025.00 32.63 917.70 3.40 6.803 4-FFf 2.50 1.94 2.50 5.17 6.65 6.03

100 year 1554.00 30.24 918.41 3.16 7.508 4-FFf 2.50 1.87 2.50 6.15 6.16 6.69

Culvert Barrel Data Culvert Barrel Type Straight Culvert

Inlet Elevation (invert): 910.90 ft, Outlet Elevation (invert): 910.60 ft

Culvert Length: 42.00 ft, Culvert Slope: 0.0071

Site Data – 24+84 Existing Site Data Option: Culvert Invert Data

Inlet Station: 0.00 ft

Inlet Elevation: 910.90 ft

Outlet Station: 42.00 ft

Outlet Elevation: 910.60 ft

Number of Barrels: 1

Culvert Data Summary – 24+84 Existing Barrel Shape: Circular

Barrel Diameter: 2.50 ft

Barrel Material: Corrugated Steel

Embedment: 0.00 in

Barrel Manning's n: 0.0240

Culvert Type: Straight

Inlet Configuration: Square Edge with Headwall (Ke=0.5)

Inlet Depression: None

Tailwater Data for Crossing: 24+84 Existing

Table 2 - Downstream Channel Rating Curve (Crossing: 24+84 Existing)

Flow

(cfs)

Water

Surface Elev

(ft)

Velocity

(ft/s)

Depth

(ft)

Shear

(psf)

Froude

Number

1025.00 915.77 5.17 6.03 1.61 0.62

1554.00 916.75 6.15 6.69 1.92 0.64

Tailwater Channel Data - 24+84 Existing Tailwater Channel Option: Trapezoidal Channel

Bottom Width: 7.00 ft

Side Slope (H:V): 5.00 (_:1)

Channel Slope: 0.0050

Channel Manning's n: 0.0350

Channel Invert Elevation: 910.60 ft

Roadway Data for Crossing: 24+84 Existing Roadway Profile Shape: Constant Roadway Elevation

Crest Length: 100.00 ft

Crest Elevation: 915.50 ft

Roadway Surface: Paved

Roadway Top Width: 15.00 ft

HY-8 Culvert Analysis Report : 48+33 Existing

Discharge Selection Method: Recurrence

Table 3 - Summary of Culvert Flows at Crossing: 48+33 - Existing

Headwater

Elevation (ft)

Discharge

Names

Total

Discharge

(cfs)

Culvert 1

Discharge

(cfs)

Roadway

Discharge

(cfs)

Iterations

920.00 25 year 4.00 4.00 0.00 1

920.66 100 year 9.00 9.00 0.00 1

922.15 Overtopping 18.47 18.47 0.00 Overtopping

Culvert Data: Culvert 1

Table 2 - Culvert Summary Table: 48+33 Existing

Discharge

Names

Total

Discharge

(cfs)

Culvert

Discharge

(cfs)

Headwater

Elevation

(ft)

Inlet

Control

Depth

(ft)

Outlet

Control

Depth

(ft)

Flow

Type

Normal

Depth

(ft)

Critical

Depth

(ft)

Outlet

Depth

(ft)

Tailwater

Depth

(ft)

Outlet

Velocity

(ft/s)

Tailwater

Velocity

(ft/s)

25 year 4.00 4.00 920.00 0.97 1.104 2-

M2c

0.95 0.70 0.70 0.57 4.07 1.46

100 year 9.00 9.00 920.66 1.56 1.759 2-

M2c

1.69 1.07 1.07 0.82 5.26 1.80

Inlet Elevation (invert): 918.90 ft, Outlet Elevation (invert): 918.70 ft

Culvert Length: 39.00 ft, Culvert Slope: 0.0051

Site Data – 48+33 Existing Site Data Option: Culvert Invert Data

Inlet Station: 0.00 ft

Inlet Elevation: 918.90 ft

Outlet Station: 39.00 ft

Outlet Elevation: 918.70 ft

Number of Barrels: 1

Culvert Data Summary – 48+33 Existing Barrel Shape: Circular

Barrel Diameter: 2.00 ft

Barrel Material: Corrugated Steel

Embedment: 0.00 in

Barrel Manning's n: 0.0240

Culvert Type: Straight

Tailwater Data for Crossing: 48+33 - Existing

Table 4 - Downstream Channel Rating Curve (Crossing: 48+33 - Existing)

Flow

(cfs)

Water

Surface Elev

(ft)

Velocity

(ft/s)

Depth

(ft)

Shear

(psf)

Froude

Number

4.00 919.27 0.57 1.46 0.12 0.43

9.00 919.52 0.82 1.80 0.18 0.45

Tailwater Channel Data - 48+33 - Existing Tailwater Channel Option: Trapezoidal Channel

Bottom Width: 2.00 ft

Side Slope (H:V): 5.00 (_:1)

Channel Slope: 0.0035

Channel Manning's n: 0.0300

Channel Invert Elevation: 918.70 ft

Roadway Data for Crossing: 48+33 - Existing Roadway Profile Shape: Constant Roadway Elevation

Crest Length: 100.00 ft

Crest Elevation: 922.15 ft

Roadway Top Width: 15.00 ft

HY-8 Culvert Analysis Report : 24+84 Proposed

Discharge Selection Method: Recurrence

Table 5 - Summary of Culvert Flows at Crossing: 24+84 Proposed

Headwater

Elevation (ft)

Discharge

Names

Total

Discharge

(cfs)

Culvert 1

Discharge

(cfs)

Roadway

Discharge

(cfs)

Iterations

917.70 25 year 1025.00 55.12 969.86 5

918.44 100 year 1554.00 49.49 1504.49 3

915.53 Overtopping 57.68 57.68 0.00 Overtopping

Culvert Data: Culvert 1

Table 3 - Culvert Summary Table: 24+84 Proposed

Discharge

Names

Total

Discharge

(cfs)

Culvert

Discharge

(cfs)

Headwater

Elevation

(ft)

Inlet

Control

Depth

(ft)

Outlet

Control

Depth

(ft)

Flow

Type

Normal

Depth

(ft)

Critical

Depth

(ft)

Outlet

Depth

(ft)

Tailwater

Depth

(ft)

Outlet

Velocity

(ft/s)

Tailwater

Velocity

(ft/s)

25 year 1025.00 55.12 917.70 4.41 6.799 4-FFf 2.23 2.41 3.00 5.44 7.80 6.33

100 year 1554.00 49.49 918.44 3.95 7.536 4-FFf 2.05 2.29 3.00 6.50 7.00 7.03

Inlet Elevation (invert): 910.90 ft, Outlet Elevation (invert): 910.60 ft

Culvert Length: 42.00 ft, Culvert Slope: 0.0071

Site Data – 24+84 Proposed Site Data Option: Culvert Invert Data

Inlet Station: 0.00 ft

Inlet Elevation: 910.90 ft

Outlet Station: 42.00 ft

Outlet Elevation: 910.60 ft

Number of Barrels: 1

Culvert Data Summary - 24+84 Proposed Barrel Shape: Circular

Barrel Diameter: 3.00 ft

Barrel Material: Concrete

Embedment: 0.00 in

Barrel Manning's n: 0.0120

Culvert Type: Straight

Tailwater Data for Crossing: 24+84 Proposed

Table 6 - Downstream Channel Rating Curve (Crossing: 24+84 Proposed)

Flow

(cfs)

Water

Surface Elev

(ft)

Velocity

(ft/s)

Depth

(ft)

Shear

(psf)

Froude

Number

1025.00 916.04 5.44 6.33 1.70 0.63

1554.00 917.10 6.50 7.03 2.03 0.65

Tailwater Channel Data - 24+84 Proposed Tailwater Channel Option: Trapezoidal Channel

Bottom Width: 8.00 ft

Side Slope (H:V): 4.00 (_:1)

Channel Slope: 0.0050

Channel Manning's n: 0.0350

Channel Invert Elevation: 910.60 ft

Roadway Data for Crossing: 24+84 Proposed Roadway Profile Shape: Constant Roadway Elevation

Crest Length: 100.00 ft

Crest Elevation: 915.53 ft

Roadway Top Width: 24.00 ft

HY-8 Culvert Analysis Report : 48+33 Proposed

Discharge Selection Method: Recurrence

Table 7 - Summary of Culvert Flows at Crossing: 48+33 - Proposed

Headwater

Elevation (ft)

Discharge

Names

Total

Discharge

(cfs)

Culvert 1

Discharge

(cfs)

Roadway

Discharge

(cfs)

Iterations

919.69 25 year 4.00 4.00 0.00 1

920.21 100 year 9.00 9.00 0.00 1

922.43 Overtopping 25.46 25.46 0.00 Overtopping

Culvert Data: Culvert 1

Table 4 - Culvert Summary Table: 48+33 Proposed

Discharge

Names

Total

Discharge

(cfs)

Culvert

Discharge

(cfs)

Headwater

Elevation

(ft)

Inlet

Control

Depth

(ft)

Outlet

Control

Depth

(ft)

Flow

Type

Normal

Depth

(ft)

Critical

Depth

(ft)

Outlet

Depth

(ft)

Tailwater

Depth

(ft)

Outlet

Velocity

(ft/s)

Tailwater

Velocity

(ft/s)

25 year 4.00 4.00 919.69 0.79 0.418 1-

S2n

0.51 0.57 0.52 0.57 4.30 1.46

100 year 9.00 9.00 920.21 1.31 0.922 1-

S2n

0.80 0.89 0.81 0.82 5.47 1.80

Inlet Elevation (invert): 918.90 ft, Outlet Elevation (invert): 918.70 ft

Culvert Length: 39.00 ft, Culvert Slope: 0.0050

Site Data – 48+33 Proposed Site Data Option: Culvert Invert Data

Inlet Station: 0.00 ft

Inlet Elevation: 918.90 ft

Outlet Station: 39.00 ft

Outlet Elevation: 918.70 ft

Number of Barrels: 1

Culvert Data Summary - 48+33 Proposed Barrel Shape: Elliptical

Barrel Span: 30.00 in

Barrel Rise: 19.00 in

Barrel Material: Concrete

Embedment: 0.00 in

Barrel Manning's n: 0.0120

Culvert Type: Straight

Tailwater Data for Crossing: 48+33 - Proposed

Table 8 - Downstream Channel Rating Curve (Crossing: 48+33 - Proposed)

Flow

(cfs)

Water

Surface Elev

(ft)

Velocity

(ft/s)

Depth

(ft)

Shear

(psf)

Froude

Number

4.00 919.27 0.57 1.46 0.12 0.43

9.00 919.52 0.82 1.80 0.18 0.45

Tailwater Channel Data - 48+33 - Proposed Tailwater Channel Option: Trapezoidal Channel

Bottom Width: 2.00 ft

Side Slope (H:V): 5.00 (_:1)

Channel Slope: 0.0035

Channel Manning's n: 0.0300

Channel Invert Elevation: 918.70 ft

Roadway Data for Crossing: 48+33 - Proposed Roadway Profile Shape: Constant Roadway Elevation

Crest Length: 100.00 ft

Crest Elevation: 922.43 ft

Roadway Top Width: 24.00 ft