Hydrologic Analysis and Two-Dimensional Simulation of Flow at State Highway 17 Crossing the Gasconade River Near Waynesville, Missouri

Prepared in cooperation with the Missouri Department of Transportation

Hydrologic Analysis and Two-Dimensional Simulation of Flow at State Highway 17 crossing the Gasconade River near Waynesville, Missouri

Scientific Investigations Report 2008–5194

U.S. Department of the Interior U.S. Geological Survey Cover photographs. Bridge over the Gasconade River (structure J-802) on Missouri State Highway 17, facing west, March 20, 2008, and January 4, 2008 (inset). Hydrologic Analysis and Two-Dimensional Simulation of Flow at State Highway 17 crossing the Gasconade River near Waynesville, Missouri

By Richard J. Huizinga

Prepared in cooperation with the Missouri Department of Transportation

Scientific Investigations Report 2008–5194

U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior DIRK KEMPTHORNE, Secretary U.S. Geological Survey Mark D. Myers, Director

U.S. Geological Survey, Reston, Virginia: 2008

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Suggested citation: Huizinga, R.J., 2008, Hydrologic analysis and two-dimensional simulation of flow at State Highway 17 crossing the Gasconade River near Waynesville, Missouri: U.S. Geological Survey Scientific Investigations Report 2008–5194, 41 p. iii

Contents

Abstract...... 1 Introduction...... 1 Purpose and Scope...... 2 Description of Study Area...... 4 Hydrologic Analysis...... 4 Basin and Gage Analysis...... 4 Recent Flood Events and Resultant Modifications to Gage Analysis...... 9 Two-Dimensional Simulation of Flow...... 10 Model of Existing Conditions...... 10 Development of the Model of Existing Conditions...... 10 Calibration of the Model of Existing Conditions to Known Floods...... 13 Flood of March 20, 2008...... 13 Flood of December 4, 1982...... 18 Flood of April 14, 1945...... 21 Simulation of Design Floods...... 21 Preliminary Evaluation of Proposed Modifications...... 25 Model of Proposed Conditions...... 25 Model Modifications...... 25 Simulation of Design Floods...... 28 Effect of Proposed Changes...... 28 Summary...... 40 References Cited...... 40

Figures

1. Photograph showing State Highway 17 crossing the Gasconade River near Waynesville, Missouri, as viewed from a bluff on the downstream right bank facing west-south-west on March 21, 2008, one day after the peak for a flood on March 20, 2008...... 2 2. Map showing location of the study area on the Gasconade River near Waynesville, Missouri...... 3 3. Aerial photograph showing study area on the Gasconade River near Waynesville, Missouri...... 5 4. Map showing digital elevation model (DEM) data depiction of the basins comprising the Gasconade River Basin and streamflow-gaging stations near Waynesville, Missouri...... 6 5. Photographs showing State Highway 17 crossing of the Gasconade River near Waynesville, Missouri, on January 4, 2008...... 7 6. Graph showing original and modified stage-discharge relation for the streamflow- gaging station on the Gasconade River near Waynesville, Missouri...... 11 iv

7–8. Maps showing— 7. Finite-element mesh used in the model of existing conditions on the Gasconade River near Waynesville, Missouri...... 12 8. Land-use coverages used in the model of existing conditions on the Gasconade River near Waynesville, Missouri...... 15 9–22. Aerial photographs showing— 9. Measured and simulated water-surface elevations for the flood of March 20, 2008, on the Gasconade River near Waynesville, Missouri...... 16 10. Measured and simulated water-surface elevations in the vicinity of State Highway 17 for the flood of March 20, 2008, on the Gasconade River near Waynesville, Missouri...... 18 11. Measured and simulated velocity vectors in the vicinity of the measurement section downstream from State Highway 17 for the flood of March 20, 2008, on the Gasconade River near Waynesville, Missouri...... 19 12. Measured and simulated velocity vectors in the vicinity of main channel structure J-802 on State Highway 17 for the flood of March 20, 2008, on the Gasconade River near Waynesville, Missouri...... 20 13. Measured and simulated velocity vectors in the vicinity of left overflow structure K-112 on State Highway 17 for the flood of March 20, 2008, on the Gasconade River near Waynesville, Missouri...... 20 14. Measured and simulated velocity vectors in the vicinity of middle overflow structure K-113 on State Highway 17 for the flood of March 20, 2008, on the Gasconade River near Waynesville, Missouri...... 21 15. Measured and simulated water-surface elevations for the flood of December 4, 1982, on the Gasconade River near Waynesville, Missouri...... 23 16. Measured and simulated water-surface elevations for the flood of April 14, 1945, on the Gasconade River near Waynesville, Missouri...... 24 17. Preliminary proposed alignment of State Highway 17 over the Gasconade River near Waynesville, Missouri, A, in relation to the existing conditions and B, as rendered with shaded ground elevation data in the model of proposed conditions...... 26 18. Land-use coverages in the vicinity of State Highway 17 used in A, the model of existing conditions and B, the model of proposed conditions on the Gasconade River near Waynesville, Missouri...... 27 19. Simulated velocity magnitudes in the vicinity of State Highway 17 from the model of proposed conditions for the A, 100-year and B, 500-year floods on the Gasconade River near Waynesville, Missouri...... 29 20. Simulated velocity magnitudes in the vicinity of State Highway 17 from the model of proposed conditions for the A, 25-year and B, 50-year floods on the Gasconade River near Waynesville, Missouri...... 30 21. Simulated water-surface elevations in the vicinity of State Highway 17 for the flood of March 20, 2008 from A, the model of existing conditions and B, the model of proposed conditions on the Gasconade River near Waynesville, Missouri...... 31 22. Simulated water-surface elevations in the vicinity of State Highway 17 for the 25-year flood from A, the model of existing conditions and B, the model of proposed conditions on the Gasconade River near Waynesville, Missouri...... 32 v

23–26. Aerial photographs showing— 23. Simulated water-surface elevations in the vicinity of State Highway 17 for the 50-year flood from A, the model of existing conditions and B, the model of proposed conditions on the Gasconade River near Waynesville, Missouri...... 33 24. Simulated water-surface elevations in the vicinity of State Highway 17 for the 100-year flood from A, the model of existing conditions and B, the model of proposed conditions on the Gasconade River near Waynesville, Missouri...... 34 25. Simulated water-surface elevations in the vicinity of State Highway 17 for the 500-year flood from A, the model of existing conditions and B, the model of proposed conditions on the Gasconade River near Waynesville, Missouri...... 35 26. Arcs used as observation profile lines in the vicinity of State Highway 17 on the Gasconade River near Waynesville, Missouri...... 36 27–32. Graphs showing— 27. Departure of simulated water-surface elevation in the model of proposed conditions from the model of existing conditions along the channel centerline and on the right flood plain upstream from State Highway 17 on the Gasconade River near Waynesville, Missouri...... 37 28. Departure of simulated velocity magnitude in the model of proposed conditions from the model of existing conditions along the channel centerline and on the right flood plain upstream from State Highway 17 on the Gasconade River near Waynesville, Missouri...... 37 29. Departure of simulated water-surface elevation in the model of proposed conditions from the model of existing conditions along the observation profile line through the left overflow structure of State Highway 17 on the Gasconade River near Waynesville, Missouri...... 38 30. Departure of simulated velocity magnitude in the model of proposed conditions from the model of existing conditions along the observation profile line through the left overflow structure of State Highway 17 on the Gasconade River near Waynesville, Missouri...... 38 31. Departure of simulated water-surface elevation in the model of proposed conditions from the model of existing conditions along the observation profile line through the middle overflow structure of State Highway 17 on the Gasconade River near Waynesville, Missouri...... 39 32. Departure of simulated velocity magnitude in the model of proposed conditions from the model of existing conditions along the observation profile line through the middle overflow structure of State Highway 17 on the Gasconade River near Waynesville, Missouri...... 39 vi

Tables

1. Basin characteristics for three streamflow-gaging stations on the Gasconade River near Waynesville, Missouri...... 8 2. The 2- to 500-year flood discharges for three streamflow-gaging stations on the Gasconade River near Waynesville, Missouri...... 8 3. Ten highest annual floods for the common period of record (1929–1975) for three streamflow-gaging stations on the Gasconade River near Waynesville, Missouri...... 9 4. Original and modified stage-discharge relation for the streamflow-gaging station on the Gasconade River near Waynesville, Missouri (06928500)...... 10 5. Original and updated flood discharges, gage heights, and water-surface elevations for the 25- to 500-year floods for the streamflow-gaging station on the Gasconade River near Waynesville, Missouri (06928500), and corresponding boundary conditions used in the models of existing and proposed conditions...... 11 6. Material and hydraulic properties of various land-use coverages in the model of the Gasconade River near Waynesville, Missouri, resulting from calibration to the floods of March 20, 2008, December 4, 1982, and April 14, 1945...... 14 7. Measured and simulated water-surface elevations for the calibration floods of March 20, 2008, December 4, 1982, and April 14, 1945, on the Gasconade River near Waynesville, Missouri...... 17 8. Measured and simulated discharge at the main measurement section and locations downstream from structures J-802, K-112, and K-113 for the calibration flood of March 20, 2008, on the Gasconade River near Waynesville, Missouri...... 19 9. Simulated discharge, cross-sectional area, and area-weighted average velocity through the main and two overflow structures of State Highway 17 for various design flows and the floods of March 20, 2008, December 4, 1982, and April 14, 1945, on the Gasconade River near Waynesville, Missouri...... 22 vii

Conversion Factors

Inch/Pound to SI Multiply By To obtain Length inch (in.) 25.4 millimeter (mm) inch (in.) 2.54 centimeter (cm) foot (ft) 0.3048 meter (m) mile (mi) 1.609 kilometer (km) Area acre 4,047 square meter (m2) acre 0.4047 hectare (ha) acre 0.004047 square kilometer (km2) square foot (ft2) 0.09290 square meter (m2) square mile (mi2) 2.590 square kilometer (km2) Flow rate foot per second (ft/s) 0.3048 meter per second (m/s) cubic foot per second (ft3/s) 0.02832 cubic meter per second (m3/s) Hydraulic gradient foot per mile (ft/mi) 0.1894 meter per kilometer (m/km) Kinematic viscosity square foot per second (ft2/s) 0.09290 square meter per second (m2/s) Unit discharge* cubic foot per second per foot 0.09290 cubic meter per second per meter [(ft3/s)/ft] [(m3/s)/m]

Vertical coordinate information is referenced to the North American Vertical Datum of 1988 (NAVD 88). Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83). *Unit discharge: The standard unit for unit discharge is cubic foot per second per foot [(ft3/s)/ ft]. In this report, the mathematically reduced form, square foot per second (ft2/s), is used for convenience. In this report, the words “left” and “right” generally refer to directions that would be reported by an observer facing downstream. viii Hydrologic Analysis and Two-Dimensional Simulation of Flow at State Highway 17 crossing the Gasconade River near Waynesville, Missouri

By Richard J. Huizinga

Abstract and 500-year recurrence floods, as well as the March 20, 2008 flood. In cooperation with the Missouri Department of Trans- Results from the model of proposed conditions show that portation, the U.S. Geological Survey determined hydrologic the proposed replacement structures and realignment of State and hydraulic parameters for the Gasconade River at the site Highway 17 will result in additional backwater upstream from of a proposed bridge replacement and highway realignment State Highway 17 ranging from approximately 0.18 foot for of State Highway 17 near Waynesville, Missouri. Information the 25-year flood to 0.32 foot for the 500-year flood. Velocity from a discontinued streamflow-gaging station on the Gascon- magnitudes in the proposed overflow structures were greater ade River near Waynesville was used to determine streamflow than in the existing structures [by as much as 4.9 feet per statistics for analysis of the 25-, 50-, 100-, and 500-year floods second in the left (west) overflow structure for the 500-year at the site. Analysis of the streamflow-gaging stations on the flood], and shallow, high-velocity flow occurs at the upstream Gasconade River upstream and downstream from Waynesville edges of the abutments of the proposed overflow structures indicate that flood peaks attenuate between the upstream gag- in the 100- and 500-year floods where flow overtops parts of ing station near Hazelgreen and the Waynesville gaging sta- the existing road embankment that will be left in place in the tion, such that the peak discharge observed on the Gasconade proposed scenario. Velocity magnitude in the main channel of River near Waynesville will be equal to or only slightly greater the model of proposed conditions increased by a maximum of (7 percent or less) than that observed near Hazelgreen. 1.2 feet per second over the model of existing conditions, with A flood event occurred on the Gasconade River in March the maximum occurring approximately 1,500 feet downstream 2008, and a flood measurement was obtained near the peak from existing main channel structure J-802. at State Highway 17. The elevation of high-water marks from that event indicated it was the highest measured flood on record with a measured discharge of 95,400 cubic feet per second, and a water-surface elevation of 766.18 feet near the Introduction location of the Waynesville gaging station. The measurements obtained for the March flood resulted in a shift of the original Locating and designing bridges and culverts on roadways stage-discharge relation for the Waynesville gaging station, that cross streams and rivers needs to take into consideration and the streamflow statistics were modified based on the new the hydrology of the basin upstream from the road cross- data. ing and the hydraulics of the channel that is being crossed. A two-dimensional hydrodynamic flow model was used The hydrology of a basin can be used to estimate the volume to simulate flow conditions on the Gasconade River in the of water that a basin will experience during floods, and the vicinity of State Highway 17. A model was developed that hydraulics of the channel can be used to estimate how the represents existing (2008) conditions on State Highway 17 channel will convey the flood discharge. Under-design of (the “model of existing conditions”), and was calibrated to the bridges and culverts could result in the disruption of traffic floods of March 20, 2008, December 4, 1982, and April 14, flow, costly maintenance to bridges and culverts, and possible 1945. Modifications were made to the model of existing con- loss of life; conversely, overdesign could result in excessive ditions to create a model that represents conditions along the costs (Alexander and Wilson, 1995). In 2007, the U.S. Geolog- same reach of the Gasconade River with preliminary proposed ical Survey (USGS), in cooperation with the Missouri Depart- replacement bridges and realignment of State Highway 17 (the ment of Transportation (MoDOT), began a study to determine “model of proposed conditions”). The models of existing and hydrologic and hydraulic parameters for existing and proposed proposed conditions were used to simulate the 25-, 50-, 100-, grade crossings of streams and rivers throughout Missouri. 2 Two-Dimensional Simulation of Flow at State Highway 17 near Waynesville, Missouri

One-dimensional computer models often are used to State Highway 17 crossing. The report describes the develop- establish the hydraulic characteristics necessary for the design ment of and results from two-dimensional hydrodynamic flow of a stream crossing (Missouri Department of Transportation, models that represent part of the Gasconade River at State 2004), and have been used in the hydraulic assessments per- Highway 17 near Waynesville, Missouri, using the depth- formed to date (2008) in the study by the USGS and MoDOT. averaged flow model Flo2DH [part of the Federal Highway Occasionally, however, the simplifying assumptions that must Administration’s Finite Element Surface-Water Modeling be made to apply a one-dimensional hydraulic analysis to a System (FESWMS) designed for hydraulic structures and two-dimensional flow scenario are deemed inadequate. This is flood plains (Froehlich, 2002)]. A two-dimensional hydrody- the case at State Highway 17 over the Gasconade River near namic flow model was developed for the Gasconade River that Waynesville, Missouri (hereinafter referred to as “the State represents conditions as they exist (as of 2008) (hereinafter Highway 17 crossing”; fig. 1). The Gasconade River meanders referred to as the “model of existing conditions”). The model substantially in the immediate vicinity of the State Highway of existing conditions was calibrated to the floods of March 17 crossing, and Roubidoux Creek flows into the Gasconade 20, 2008, December 4, 1982, and April 14, 1945, and used to River immediately upstream from State Highway 17 (fig. 2). simulate the 25-, 50-, 100-, and 500-year recurrence floods. This unique configuration is beyond the reasonable bounds for Based on information provided by MoDOT (David Stevenson, a one-dimensional hydraulic analysis, indicating the need for a Missouri Department of Transportation, written commun,. two-dimensional hydraulic analysis of the site. 2008; Keith Ferrell, Missouri Department of Transportation, written commun,. 2008), the model of existing conditions was modified to create another model that represents conditions Purpose and Scope along the same reach of the Gasconade River with preliminary proposed replacement structures in place (hereinafter referred This report describes and presents the results of a hydro- to as the “model of proposed conditions”). The model of pro- logic analysis and two-dimensional simulation of flow at the posed conditions was used to simulate the flood of March 20,

Flow direction Left overflow structure K-112 Middle overflow structure K-113

Main channel structure J-802

Flow direction

Figure 1. State Highway 17 crossing the Gasconade River near Waynesville, Missouri, as viewed from a bluff on the downstream right bank facing west-south-west on March 21, 2008, one day after the peak for a flood on March 20, 2008. Introduction 3

92°16' 92°15' 92°14' 92°13' 92°12'

Unnamed

Unnamed 37°53'

tributary trib RIVER

utary GASCONADE RIVER 17 Unnamed

NADE

CO tributary GAS GASCONADE

37°52'

RIVER Unnamed

tributary

Roub 37°51' idoux

Collie Creek Hollow Hollow

Trower tributary tributary

Unnamed

Unnamed 17 37°50'

Waynesville

17 Bus T 44 Bus 44

Base from U.S. Geological Survey digital data, 1:24,000, 1996 0 2,000 4,000 FEET Universal Transverse Mercator projection, Zone 15 Horizontal coordinate information referenced to the 0 500 1,000 METERS North American Datum of 1983 (NAD 83)

EXPLANATION Study area boundary LOCATION MAP Primary highways Minor roads Flow direction MISSOURI Pulaski County

Map area

Figure 2. Location of the study area on the Gasconade River near Waynesville, Missouri. 4 Two-Dimensional Simulation of Flow at State Highway 17 near Waynesville, Missouri

2008, and the 25-, 50-, 100-, and 500-year recurrence floods pasture, with areas of timber and brush (fig. 3). A riparian under the proposed conditions. The difference between the corridor of variable thickness is present along the Gasconade hydraulic parameters (particularly water-surface elevation and River and Roubidoux Creek (fig. 3). The bluffs on either side velocity magnitude) determined for the existing conditions and of the flood plain are covered with thick timber and brush the proposed conditions are shown. (figs. 1 and 3). In this report, all vertical coordinate information is referenced to the North American Vertical Datum of 1988 (NAVD Description of Study Area 88). In the study area, the difference between the NAVD 88 and the National Geodetic Vertical Datum of 1929 (NGVD 29) The study area is located on the Gasconade River in the is approximately 0.10 meters (m) or 0.33 ft. central part of Pulaski County, Missouri, north of Waynes- ville, where Roubidoux Creek flows into the Gasconade River (figs. 2 and 3). The study area begins approximately 2.4 miles (mi) downstream from the State Highway 17 crossing, near Hydrologic Analysis the location of a discontinued gage on the Gasconade River (06928500, Gasconade River near Waynesville), and extends Hydrologic analysis of the State Highway 17 crossing of approximately 3,600 feet (ft) upstream from State Highway 17 the Gasconade River near Waynesville involved an analysis of on the Gasconade River. The study area also extends approxi- the Gasconade River Basin upstream from the State Highway mately 1.5 mi along Roubidoux Creek upstream from its 17 crossing as well as of the various streamflow-gaging sta- confluence with the Gasconade River (figs. 2 and 3). tions (hereinafter referred to as “gages”) on the Gasconade State Highway 17 is the primary highway across the River near Waynesville. These analyses were updated after a Gasconade River between Crocker and Waynesville, which record flood event occurred in March 2008. has access to Interstate 44 (fig. 4). The nearest alternate bridge is approximately 12.4 river miles away, and the shortest detour resulting from the closure of this road is approximately 23 Basin and Gage Analysis mi (David Stevenson, written commun., 2008); therefore, A gage was operated by the USGS on the Gasconade MoDOT wanted to minimize disruption to traffic and mini- River near Waynesville from 1915 to 1975 (station num- mize road closure times during the replacement of the struc- ber 06928500, hereinafter referred to as “the Waynesville tures on State Highway 17. Results described in this report are gage”). Information from this gage was used to determine needed by MoDOT to develop design and replacement plans at peak discharges for calibrating the two-dimensional hydraulic the State Highway 17 crossing. models of the State Highway 17 crossing, and to determine In the vicinity of the study area, the dominant phys- the streamflow statistics for analysis of the 25-, 50-, 100-, and iographic feature is the Ozarks Plateaus, characterized by 500-year floods at the site. The 25-year flood is the discharge gravel-bed streams with flood plains bordered with limestone that has a 1 in 25 chance of occurring in any given year [0.04 and dolomite bluffs (figs. 3 and 5). State Highway 17 crosses (4 percent) probability]; similarly, the 50-year flood is the dis- the Gasconade River from east to west at a point where the charge that has a 1 in 50 chance [0.02 (2 percent) probability], Gasconade River makes an approximately 170 degree bend, the 100-year flood is the discharge that has a 1 in 100 chance just downstream from the confluence with Roubidoux Creek [0.01 (1 percent) probability], and the 500-year flood is the (figs. 2 and 3). The main bridge over the Gasconade River is discharge that has a 1 in 500 chance of occurring in any given structure J-802, a 482-ft long bridge, consisting of a 200-ft year [0.002 (0.2 percent) probability]. through-truss main span, two 100-ft pony truss approach Basin characteristics derived from 30-m digital elevation spans, and two 35-ft steel I-beam approach spans with con- model (DEM) data (Missouri Spatial Data Information Ser- crete piers founded on rock (figs. 1, 3, and 5A). Two overflow vice, 2008) were determined for the Waynesville gage, as well bridges exist on the left (west) flood plain: structure K-112 is as the gages on the Gasconade River near Hazelgreen (station furthest to the left (west), and consists of nine 40-ft long steel number 06928000, hereinafter referred to as “the Hazelgreen I-beam spans with concrete bents founded on rock (figs. 1, 3, gage”) and at Jerome (station number 06933500, hereinafter and 5B); structure K-113 is between K-112 and main bridge referred to as “the Jerome gage”) (fig. 4), and are compared J-802, and also consists of nine 40-ft long steel I-beam spans to values reported in Alexander and Wilson (1995; table 1). with concrete bents founded on rock (figs. 1, 3, and 5C). An Streamflow statistics for these three gages as determined by elevated, level road embankment exists between structures Alexander and Wilson (1995) using log-Pearson Type III J-802 and K-113, and between K-113 and K-112. A series of distribution analyses (Hydrologic Subcommittee of Inter- horizontal curves cause the road to weave north and south as agency Advisory Committee on Water Data, 1982) are shown State Highway 17 crosses the flood plain from east to west in table 2. As would be expected, the drainage area increases (figs. 1 through 3). and the channel slope decreases in a downstream direction In the study area, the flood plain predominantly consists (table 1); however, the streamflow statistics for the three gages of agricultural land used for growing corn, soybeans, and do not follow a particular trend (table 2). The 2- and 5-year Hydrologic Analysis 5

92°14’ 92°13' 92°12'

GASCONADE RIVER Log cabin

Waynesville gage

Scrub brush

Timber-covered bluffs

37°52' Timber-covered bluffs

Agricultural land (pasture) Abandoned rental house Timber-covered bluffs Timber-covered bluffs

Timber and brush Timber Area shown in figures 10, 17–25

Timber-covered bluffs Agricultural land (pasture) GASCONADE RIVER Timber-covered bluffs Roubidoux 37°51'

Structure Structure Structure Creek K-112 K-113 J-802 Agricultural land (row crops)

Timber-covered bluffs Timber-covered bluffs Agricultural Timber-covered bluffs land (row crops)

Timber

EXPLANATION Study area boundary State Highway 17 U.S. Geological Survey streamflow-gaging station Point of interest

Figure 3. Study area on the Gasconade River near Waynesville, Missouri. 6 Two-Dimensional Simulation of Flow at State Highway 17 near Waynesville, Missouri

92°40' 92°20' 92°0'

Camdenton 38°0' 17 Gasconade River at Jerome 63 54 133 (06933500) Gasconade River near Waynesville Rolla (06928500—discontinued) Crocker 28 7 44 133 Area shown in figure 2 Little Piney Creek 5

Richland 72 Waynesville

Roubidoux Creek below Fort Leonard Wood 63 17 (06928430) Big Piney River 64 Gasconade River near Hazelgreen

Lebanon Roubidoux Creek 37°40' (06928000) 32

32 32 32 119

5 44 GASCONADE RIVER 137 95 63 17 37°20' 38 Houston

38 63

17 95

137 60 5

60 Mansfield 60 Mountain Cabool Grove 60 5 95 181

Base from U.S. Geological Survey digital data, 1:24,000, 1996 0 5 10 15 20 MILES Universal Transverse Mercator projection, Zone 15 Horizontal coordinate information referenced to the North American Datum of 1983 (NAD 83) 0 10 20 30 KILOMETERS

EXPLANATION Elevation, in feet above Basin boundary—Shaded portion is basin NAVD 88 upstream from Waynesville gage 1,750 1,600 Interstate highway 1,450 1,300 Primary highways 1,150 U.S. Geological Survey streamflow-gaging station 1,000 850 Cities or towns of interest 700

Figure 4. Digital elevation model (DEM) data depiction of the basins comprising the Gasconade River Basin and streamflow-gaging stations near Waynesville, Missouri. Hydrologic Analysis 7

B C

Figure 5. State Highway 17 crossing of the Gasconade River near Waynesville, Missouri, on January 4, 2008; A, Upstream face of main channel structure J-802, spanning the gravel bed of the river, as viewed from the right bank immediately upstream from the right (east) abutment at the base of a limestone and dolomite bluff, B, upstream face of left (west) overflow structure K-112, as viewed from the upstream top of the right (east) abutment; and C, downstream face of middle overflow structure K-113, as viewed from the downstream top of the right (east) abutment. discharges increase in a downstream direction, but for the 10- gages, the area increases by 69 percent (from 1,680 to 2,840 to 500-year recurrence intervals, the discharge values at the mi2), and the channel length increases by only 24 percent Waynesville gage are less than those at the Hazelgreen gage. (from 136 to 169 mi). Most of the difference in area between The attenuation of flow that is evident in the streamflow the Hazelgreen and Waynesville gages is from Roubidoux statistics between the Hazelgreen and Waynesville gages likely Creek (290 mi2), which joins the Gasconade River at State is a function of the drainage area and channel length; whereas Highway 17, just upstream from the Waynesville gage. The the area increases by 35 percent between the Hazelgreen and flow length of the Gasconade between the Hazelgreen and Waynesville gages [from 1,250 to 1,680 square miles (mi2)], Waynesville gages generally allows peak flows on Roubidoux the channel length increases by 47 percent (from 92.8 to 136 Creek to dissipate well before the arrival of a flood peak from mi). By comparison, between the Waynesville and Jerome Hazelgreen, resulting in attenuation of the flood peak at the 8 Two-Dimensional Simulation of Flow at State Highway 17 near Waynesville, Missouri

Table 1. Basin characteristics for three streamflow-gaging stations on the Gasconade River near Waynesville, Missouri.

[DEM, digital elevation model; mi2, square miles, ft/mi, feet per mile; mi, mile]

Gasconade River near Gasconade River near Gasconade River at Jerome Hazelgreen (06928000) Waynesville (06928500) (06933500) Basin characteristic Alexander 30-meter Alexander 30-meter Alexander 30-meter and Wilson DEM and Wilson DEM and Wilson DEM (1995) data (1995) data (1995) data Drainage area (mi2) 1,250 1,250 1,680 1,700 2,840 2,830 Main channel slope (ft/mi) 3.97 4.23 3.18 3.47 3.01 3.17 Main channel length (mi) 92.8 92.8 136 136 169 169

Table 2. The 2- to 500-year flood discharges for three streamflow-gaging stations on the Gasconade River near Waynesville, Missouri (from Alexander and Wilson, 1995).

[USGS, U.S. Geological Survey; WY, water years; ft3/s, cubic feet per second]

USGS Period of Flood discharge (ft3/s) for indicated recurrence interval (years) USGS station record used station name number (WY) 2 5 10 25 50 100 500 Gasconade River near Hazelgreen 06928000 1929–1983 21,600 40,100 53,700 72,000 85,900 100,000 133,000 Gasconade River near Waynesville 06928500 1915–1975 23,300 40,800 53,400 69,800 82,300 94,700 124,000 Gasconade River at Jerome 06933500 1923–1993 31,200 53,000 68,900 90,500 107,000 125,000 168,000

Waynesville gage. Discussions with long-term local residents The Jerome gage had another peak discharge in August confirm this observation (Richard and Jim Hamilton, oral 1946 (stage 26.55 ft, discharge 87,500 ft3/s) for which the commun., 2008). discharge ranges between the 1945 and 1935 discharges at Attenuation is not a constant, and the peak discharge that gage, but this flood did not register in the top 10 floods at measured at the Hazelgreen gage is not always equal to or either the Hazelgreen or Waynesville gages (table 3). The top greater than that at the Waynesville gage, as implied by the four floods for the Waynesville gage (highlighted in table 3) in streamflow statistics. Examining the common period of record the common period of record for the three gages (1929–1975) between the gages (1929–1975) shows that the highest peak are not necessarily the top four floods for the Hazelgreen or event occurred on the Gasconade River in mid-April 1945, Jerome gages. These differences are caused by variable rain- and was recorded at all three gages (table 3). The peak at the fall over the substantial area covered by the Gasconade River Hazelgreen gage occurred April 14, with a stage of 29.6 ft, and Basin (fig. 5), resulting in localized flooding of tributaries. a discharge of 76,400 cubic feet per second (ft3/s). The peak A particularly large flood occurred on the Gasconade at the Waynesville gage also occurred April 14, with a stage River in early December 1982, which up until 2008 had been of 23.5 ft and a discharge of 81,600 ft3/s, which is 6.8 percent viewed as the flood of record on the Gasconade. The entire larger than the Hazelgreen gage. The peak at the Jerome gage December 1982 event was recorded at the Jerome gage, and a occurred April 15, with a stage of 27.7 ft and a discharge of peak stage was recorded at the Hazelgreen gage; however, the 101,000 ft3/s (23.8 percent larger than the Waynesville gage). Waynesville gage had not been operational for several years, The next highest peak event on the Gasconade River that and no peak stage or discharge was recorded there. The peak was common to and recorded at all three stations occurred in stage recorded at the Jerome gage was 31.34 ft, which corre- mid-March 1935 (table 3). The peak at the Hazelgreen gage sponds to a discharge of 136,000 ft3/s (U.S. Geological Survey, occurred March 12, with a stage of 27.5 ft and a discharge 2008b). The peak stage recorded at the Hazelgreen gage was of 68,700 ft3/s. The peak at the Waynesville gage occurred 34.46 ft, which corresponds to a discharge of approximately March 13, with a stage of 21.62 ft and a discharge of 69,000 87,000 ft3/s, based on an extension of the stage-discharge rela- ft3/s (0.4 percent larger than the Hazelgreen gage). The peak at tion at that gage (U.S. Geological Survey, 2008a). During a the Jerome gage also occurred March 13, with a stage of 25.8 field visit in January 2008, approximate high-water elevations ft and a discharge of 76,800 ft3/s (11.3 percent larger than the were recovered for the December 1982 flood at a log cabin Waynesville gage). near the location of the Waynesville gage and at an aban- Hydrologic Analysis 9

Table 3. Ten highest annual floods for the common period of record (1929–1975) for three streamflow- gaging stations on the Gasconade River near Waynesville, Missouri.

[ft3/s, cubic feet per second; shaded areas highlight four annual floods common to all three stations]

Gasconade River near Gasconade River near Gasconade River at Jerome Hazelgreen (06928000) Waynesville (06928500) (06933500) Flood event Peak Peak Peak rank Water Water Water discharge discharge discharge year year year (ft3/s) (ft3/s) (ft3/s) 1 1945 76,400 1945 81,600 1945 101,000 2 1935 68,700 1935 69,000 1946 87,500 3 1947 58,000 1943 64,700 1935 76,800 4 1941 54,500 1941 57,700 1943 74,000 5 1933 53,800 1947 55,700 1961 62,800 6 1943 51,000 1933 52,200 1933 62,600 7 1958 49,000 1958 45,100 1947 60,000 8 1969 46,200 1957 44,500 1957 57,400 9 1950 44,600 1961 43,300 1941 54,600 10 1961 39,400 1969 41,700 1950 48,700 doned rental house approximately midway between the State Waynesville gage and the State Highway 17 crossing, and near Highway 17 crossing and the Waynesville gage (fig. 3). The the upstream end of the study area on Roubidoux Creek. A unusual trend in the streamflow statistics and the measured comparison of the 2008 high-water marks to the approximate peak discharges for the Waynesville gage with respect to the high-water marks recovered for the 1982 flood indicated that Hazelgreen and Jerome gages results in a lack of confidence the 2008 flood also exceeded the 1982 flood near Waynesville in any estimate of the discharge at the Waynesville gage for by approximately 0.5 ft. The measurement made on March 20, the 1982 flood; therefore, for this report the peak from April 2008, was sufficiently near the peak to match the high-water 14, 1945, initially was considered the peak of record at the marks recovered for the peak. Waynesville gage. The discharge measured near the peak flow conditions downstream from the State Highway 17 crossing was 95,400 ft3/s (approximately 6.5 percent larger than at the Hazelgreen Recent Flood Events and Resultant gage), and the corresponding peak stage near the Waynesville Modifications to Gage Analysis gage was 27.25 ft. The peak at the Jerome gage also occurred March 20, with a stage of 30.43 ft and a discharge of 118,000 A major rainfall event occurred March 18–19, 2008, ft3/s (approximately 23.7 percent larger than the Waynes- with recorded amounts of up to 12 inches (in.) of rain falling ville gage). Based on the latest stage-discharge relation for over most of southern Missouri (National Weather Service, the Waynesville gage, the measured peak stage should have 2008). This rainfall event caused extreme flooding for many resulted in a discharge of approximately 121,000 ft3/s, which of the streams in southern Missouri, including the Gasconade is substantially greater than the 95,400 ft3/s measured at State River. On March 19, the Hazelgreen gage crested at a stage Highway 17, as well as the 118,000 ft3/s measured at the of 34.92 ft, approximately 0.46 ft higher than the previous Jerome gage; therefore, it was assumed that the Gasconade flood of record on December 3, 1982. The discharge mea- River had undergone a change in flow control since the time sured at Hazelgreen near the peak was 89,500 ft3/s. On March the Waynesville gage was discontinued in 1975, and a modi- 20, a discharge measurement was made on the Gasconade fied stage-discharge relation was developed that incorporated River just downstream from the State Highway 17 crossing, the leftward shift seen in the 2008 flood (table 4 and fig. 6). approximately 1 hour after the Gasconade River peaked at this The leftward shift caused by the 2008 flood partially may be location. High-water marks indicating the peak flood eleva- the result of the discharge measurement being made after the tion were recovered along the upstream and downstream sides peak occurred at the State Highway 17 crossing, which can of the Highway 17 road embankment on March 21, 2008. On result in a lower discharge being measured at a given stage April 9, 2008, additional high-water marks were recovered at than would be observed before the peak occurs (backwater the log cabin near the location of the Waynesville gage, at the effect). Using the modified relation resulted in a discharge of abandoned rental house approximately midway between the 92,300 ft3/s for the December 1982 flood at the Waynesville 10 Two-Dimensional Simulation of Flow at State Highway 17 near Waynesville, Missouri gage, which is more in line with the discharge of 87,000 ft3/s obstructions. A graphic user interface called the Surface-Water measured at the Hazelgreen gage for that flood (approximately Modeling System (SMS; Environmental Modeling Research 6.1 percent greater). These two similar floods in recent history Laboratory, 1999) was used to construct the two-dimensional seem to confirm the change in flow control. finite-element mesh, facilitate assignment of roughness coefficients and other hydraulic and material parameters to the mesh Table 4. Original and modified stage-discharge relation elements, execute the model, and evaluate the model output for the streamflow-gaging station on the Gasconade River numerically and graphically. near Waynesville, Missouri (06928500).

[ft, feet; ft3/s, cubic feet per second; --, not determined] Model of Existing Conditions

Gage height Original discharge Modified discharge The model of existing conditions was used to provide (ft) (ft3/s) (ft3/s) results for the study area with channel conditions and bridge 2.0 140 140 structures as they currently (2008) exist. Results from the model of existing conditions were used with information 5.0 1,930 1,930 provided by MoDOT to assess the need for replacement over- 7.5 4,850 4,850 flow structures at the State Highway 17 crossing. The model 10.0 8,350 8,350 of existing conditions in turn was used as the base model to 13.0 13,500 13,500 develop the model of proposed conditions. Primary reconnaissance of the study area in the vicinity 15.0 18,500 18,500 of the State Highway 17 crossing was conducted by MoDOT, 16.0 23,000 22,100 but additional field reconnaissance and surveying of the study 20.0 47,900 40,800 area was done by the USGS on January 3–4, 2008. During the 22.5 70,400 56,400 USGS field visit, the channel bathymetry was defined, and information and photographs were gathered for the bridges, 25.0 99,000 75,300 road embankment, channel, and flood plain in the vicinity of a a 27.25 -- 95,400 the State Highway 17 crossing. 27.5 -- 97,800 30.0 -- 124,000 Development of the Model of Existing Conditions 30.5 -- 130,000 a This point on the modified stage-discharge relation is from the The extent of the mesh for the model of existing condi- discharge measurement made on March 20, 2008. tions was from bluff to bluff, starting from a point just downstream from the Waynesville gage to a point approximately 3,600 ft upstream from State Highway 17 on the Gasconade Additionally, the streamflow statistics for the Waynesville River, and extended approximately 1.5 mi up Roubidoux gage were recomputed, incorporating the 2008 flood peak. The Creek (figs. 2 and 3). Ground-elevation information for the updated 25- to 500-year flood recurrence intervals are shown study area was obtained from 10-m DEM data (Missouri Spa- in table 5, with the corresponding water-surface elevations at tial Data Information Service, 2008) of the area supplemented the location of the Waynesville gage resulting from the modi- with surveyed information on and adjacent to State Highway fied stage-discharge relation. These values were used in the 17 obtained during the field visit in January 2008. Bathymetry two-dimensional flow model analysis of existing and proposed data of the channel bed also were collected during the January conditions. 2008 field visit. These data formed the base topographic data- set for the model of existing conditions. Mesh elements were designed with consideration to the level of detail of the hydraulic information required from the Two-Dimensional Simulation of Flow simulation results (fig. 7). The area around State Highway 17 was of critical interest, so smaller elements were used in this The FESWMS Flo2DH model simulates flow in two part of the study area, whereas larger elements were used to dimensions in the horizontal plane, using a finite-element represent the channel and flood plains away from State High- mesh and the Galerkin finite-element method of solving three way 17 (fig. 7). partial-differential equations representing conservation of The piers and bents for the main channel structure J-802 mass and momentum (Froehlich, 2002). This two-dimensional were hard-coded as elements directly into the model mesh. flow model can simulate longitudinal and lateral variations in Position, orientation, and dimensions of each pier and bent water-surface elevations and velocities, and can accommodate were obtained from bridge plans (Missouri Department of geometric features such as highway embankments, bridge Transportation, 1932a) to accurately position and size the piers structures, channel bends, berms, buildings, and other flow and bents. The circular columns of the main piers of structure Two-Dimensional Simulation of Flow 11

30 Modified rating based on flood of March 20, 2008

20 Original rating

GAGE HEIGHT, IN FEET ABOVE DATUM 3

1 100 1,000 10,000 100,000

DISCHARGE, IN CUBIC FEET PER SECOND

Figure 6. Original and modified stage-discharge relation for the streamflow-gaging station on the Gasconade River near Waynesville, Missouri.

Table 5. Original and updated flood discharges, gage heights, and water-surface elevations for the 25- to 500- year floods for the streamflow-gaging station on the Gasconade River near Waynesville, Missouri (06928500), and corresponding boundary conditions used in the models of existing and proposed conditions. Elevation referenced to North American Vertical Datum of 1988 (NAVD 88).

[ft3/s, cubic feet per second; ft, feet]

Original flood Upstream boundary— Updated values at gaging station Downstream discharge value discharge Recurrence boundary— at gaging station interval Water- water-surface (from Alexander Flood dis- Gage Gasconade Roubidoux (years) surface elevation and Wilson, 1995) charge height River Creek 3 elevation 3 3 3 (ft /s) (ft) (ft /s) (ft /s) (ft) (ft /s) (ft) 25 69,800 72,100 24.61 763.54 68,630 3,470 763.1 50 82,300 85,300 26.16 765.09 81,190 4,110 764.6 100 94,700 98,700 27.59 766.52 93,950 4,750 766.0 500 124,000 130,000 30.50 769.43 123,740 6,260 768.9 12 Two-Dimensional Simulation of Flow at State Highway 17 near Waynesville, Missouri

92°14’ 92°13' 92°12' Unnamed tributary

Unnamed tributary 37°52' J-802 K-113 K-112

Unnamed tributary

GASCONADE RIVER

37°51'

Hollow Roubidoux Creek Trower

tributary tributary

Unnamed

Base from U.S. Geological Survey digital data, 1:24,000, 1996 0 1,000 2,000 3,000 4,000 FEET Universal Transverse Mercator projection, Zone 15 Horizontal coordinate information referenced to the North American Datum of 1983 (NAD 83) 0 250 500 750 1,000 METERS

EXPLANATION

Study area boundary Minor roads Mesh elements and nodes—Elements State Highway 17 Bridge structures have nodes at each corner and at the midpoint of each side

Figure 7. Finite-element mesh used in the model of existing conditions on the Gasconade River near Waynesville, Missouri. Two-Dimensional Simulation of Flow 13

J-802 were approximated as octagons, whereas the square late between wet and dry, which can lead to solution instability columns of the left and right overbank bents were coded as and a loss of convergence. To limit this instability, the user sets squares; the elements within each of these piers and bents a tolerance on the depth of flow over a node (the storativity were disabled to force flow around them. depth, table 6); however, if an element goes dry and stays dry The bents for overflow structures K-112 and K-113 were for several iterations, it is manually disabled to prevent model incorporated into the model mesh using the pier module in instability. Once the spindown process is complete, the model Flo2DH. These overflow structure bents would affect flow in calibration can be refined by adjusting other model parameters the model, but would have resulted in inordinate mesh refine- such as Manning’s roughness coefficient and kinematic eddy ment to incorporate directly into the model mesh as disabled viscosity. elements, as had been done for the main channel structure Material and hydraulic properties were assigned to the piers and bents. Once again, position, orientation, and dimen- model based on land use from aerial photography (fig. 8), and sions of each bent were obtained from bridge plans (Missouri initial Manning’s roughness coefficients were assigned based Department of Transportation, 1932b, 1932c) to accurately on published guidance (Chow, 1959; Barnes, 1967; Arce- position and size the bents. Each column of the bents of struc- ment and Schneider, 1989) and previously calibrated models tures K-112 and K-113 were coded as square-nosed columns of similar river reaches (Huizinga, 2007a, 2007b, Huizinga 2.5 ft wide and 2.5 ft long in the pier module, as noted from and Rydlund, 2001). A depth-dependent Manning’s rough- the bridge plans. ness coefficient (n-value) method was used, wherein the The finite-element mesh for the model of existing condi- “lower depth” n-value is applied when the water depth over tions consisted of 23,755 elements that ranged in size from the nodes around an element is less than the lower depth, and 2.96 to 10,295 square feet (ft2). Each element had a node at the “upper depth” n-value is applied when the water depth is each corner and at the midpoint of each side, which created a greater than the upper depth; when the water depth is between total of 53,814 nodes. the lower and upper depths, the n-value is interpolated linearly from the upper and lower n-values (Froehlich, 2002). Depth- dependent n-values were used to account for changes in the Calibration of the Model of Existing Conditions to roughness with increased depth of flow; generally, the rough- Known Floods ness decreases with increased depth because the effect of the physical features causing the roughness decreases as the depth The simulation of a particular flow scenario with Flo2DH of flow increases (for example, grass and crops that lie over in requires an iterative process called spindown (Huizinga, high flows). In addition, each coverage initially was assigned 2007a, 2007b; Huizinga and Rydlund, 2001). In a subcritical a large value of kinematic eddy viscosity that would promote flow regime (deep, slow flow typical of non-alpine streams model stability [150 square feet per second (ft2/s)] during and rivers), spindown involves initializing the model with the the spindown process. After spinning the model down to the desired discharge as the upstream boundary condition and a desired boundary conditions, the eddy viscosity was adjusted downstream water-surface elevation that is higher than the to more appropriate values (table 6) consistent with guidelines highest land-surface elevation in the mesh. This ensures that in Froehlich (2002). all nodes in the model are “wet” (having a positive depth of Initially, the model of existing conditions was calibrated flow) and produces a flat water-surface elevation across the to a flood that occurred on the Gasconade River on April 14, model grid, which promotes numerical stability for the initial 1945; however, on March 20, 2008, the Gasconade River model computations. The model is run with these conditions experienced an extreme flood before completion of the model for a sufficient number of iterations to cause the water-surface of proposed conditions. The model of existing conditions was elevation changes between iterations to be minimized within recalibrated using the flood that occurred on the Gasconade a preset limit. Once the limit is reached, the model is said to River on March 20, 2008, as well as the floods of December 4, have “converged.” The downstream water-surface elevation is 1982, and April 14, 1945. then decreased by some finite amount, the model is restarted using the results of the previous run—called a hotstart—as the starting point for the new run, and the model is run until Flood of March 20, 2008 convergence occurs. This process is repeated until the desired A discharge measurement was made approximately downstream water-surface elevation is reached, as dictated by 1,500 ft downstream from State Highway 17 on March 20, high-water marks, flood profiles, or other known site param- 2008, near the time that the peak occurred at that location. eters. During the spindown process, if the simulated water- The measured discharge was 95,400 ft3/s, and is the average of surface elevation at a particular node is less than the land- four individual measurement sections or “passes” across the surface elevation assigned to the node, then the node is said to flood plain downstream from State Highway 17. The dis- “go dry.” If one or more of the nodes for a particular element charge from Roubidoux Creek was estimated at 4,600 ft3/s (4.8 go dry, the entire element is assumed to go dry, and it is not percent of the total flow) at the time of the Gasconade River included in the computations during that iteration. As the measurement, based on the stage and stage-discharge relation simulation proceeds through iterations, an element can oscil- of the gage near Waynesville (Roubidoux Creek below Fort 14 Two-Dimensional Simulation of Flow at State Highway 17 near Waynesville, Missouri

Table 6. Material and hydraulic properties of various land-use coverages in the model of the Gasconade River near Waynesville, Missouri, resulting from calibration to the floods of March 20, 2008, December 4, 1982, and April 14, 1945.

[ft, feet; ft2/s, square foot per second]

Lower depth Upper depth Kinematic eddy Storativity Land-use coverage Manning’s Depth Manning’s Depth viscosity depth n (ft) n (ft) (ft2/s) (ft) Channel and bank Main channel 0.045 3 0.035 6 10 1.0 Open timber and brush .100 4 .075 8 30 1.0 Thick timber and thick brush .180 6 .150 12 50 1.0 Flood plain Pasture 0.045 1 0.040 4 10 1.0 Row crops (corn) .060 2 .040 8 10 2.0 Thick grasses with sprouts .080 3 .065 6 10 1.0 Highway embankment .050 1 .045 4 10 1.0 Bridge deck area .045 1 .040 4 10 .5 Pavement and gravel .025 1 .020 2 10 .5 Grassy area with interspersed trees .055 3 .040 6 10 1.0 Scrub brush .100 2 .075 8 10 2.0

Leonard Wood, 06928430, fig. 4); the balance of 90,800 ft3/s point, because it appeared to reflect the peak of the flood on was assumed to be flowing in the Gasconade River chan- Roubidoux Creek and was not indicative of the flooding on the nel upstream from the confluence. High-water marks were Gasconade River. recovered after the flood recession along the upstream and Velocity magnitude and direction from one of the four downstream faces of the State Highway 17 road embankments, measurement sections from the discharge measurement at the log cabin near the Waynesville gage, at the abandoned obtained downstream from State Highway 17 on March 20, rental house midway between the Waynesville gage and the 2008, are shown with simulated results in figure 11. The aver- State Highway 17 crossing, and near the upstream end of the age measured discharge is shown in table 8 with the simu- study area on Roubidoux Creek. The water-surface elevation lated discharge determined at a flux line created near the four at structure J-802 was measured just after the peak on the measurement sections in the model of existing conditions. The receding limb of the flood from a surveyed reference point on magnitude and direction of the simulated velocities are similar the bridge. to velocities along the representative measurement section For the model of existing conditions, the upstream bound- shown in figure 11, and the average measured and simulated ary on the Gasconade River was set to the estimated discharge discharges are similar (table 8). of 90,800 ft3/s, the upstream boundary on Roubidoux Creek Velocity magnitude and direction from partial discharge was set to 4,600 ft3/s, and the downstream boundary initially measurements obtained near each existing bridge are shown was set to 820.0 ft. The model of existing conditions then was with simulated results in figures 12 through 14. The discharge spun down to a downstream boundary condition of 765.6 ft to for the partial measurement at each existing bridge is shown in obtain a match with the surveyed high-water marks at the log table 8 with the simulated discharge determined at a flux line cabin near the Waynesville gage. created near each partial measurement section in the model To refine the model calibration, the material properties of existing conditions. Generally, the magnitude and direction were adjusted to the values in table 6 to cause the water-sur- of the simulated velocities are similar to velocities along the face elevations in the model to match the measured water- measurement sections, except near the bents of the existing surface elevations based on the surveyed high-water marks. overflow structures; the measured flow magnitude is lower Measured and simulated water-surface elevations for the entire than simulated on the parts of the partial measurement sec- study area for the 2008 flood are shown in figure 9 and table tions immediately downstream from the bents, particularly for 7. Measured and simulated water-surface elevations in the the existing overflow structures (figs. 13 and 14) and the left vicinity of the State Highway 17 crossing are shown in figure overbank bent of the existing main channel structure (fig. 12). 10. The high-water mark recovered at the upstream end of the Simulated results for the full bridge opening for each of the study area on Roubidoux Creek was not used as a calibration three existing bridges are shown in table 9. Two-Dimensional Simulation of Flow 15

92°14’ 92°13' 92°12' Unnamed GASCONADE RIVER tributary

Unnamed tributary 37°52'

Unnamed tributary

GASCONADE RIVER

37°51'

Hollow Roubidoux Creek Trower

tributary tributary

Unnamed

EXPLANATION

Land Use Area of no flow Thick timber and thick brush Grassy area with interspersed trees Sand and gravel channel Open timber and brush Highway embankment Row crops (corn) Scrub brush (small trees and scrub) Pavement and gravel Pasture Thick grasses with sprouts Bridge deck

Study area boundary State Highway 17 Minor roads

Figure 8. Land-use coverages used in the model of existing conditions on the Gasconade River near Waynesville, Missouri. 16 Two-Dimensional Simulation of Flow at State Highway 17 near Waynesville, Missouri

92°14’ 92°13' 92°12'

GASCONADE RIVER Measured, 766.18 ft Simulated, 766.18 ft

766.0

766.5

767.0

37°52' 767.5 768.0

768.5

769.0

Measured, 769.35 ft Simulated, 769.20 ft

769.5 Area shown in figure 11 Area shown in figure 10

771.5 770.5 772.0 772.5 GASCONADE RIVER 770.0 771.0 Measured, 771.83 ft 37°51' Simulated, 772.00 ft

773.0

773.5

774.0

Base from National Agricultural Imagery Program, 2006 0 1,000 2,000 3,000 4,000 FEET Universal Transverse Mercator projection, Zone 15 Horizontal coordinate information referenced to the North American Datum of 1983 (NAD 83) 0 250 500 750 1,000 METERS EXPLANATION Simulated water-surface elevation, in feet above NAVD 88 774.5 Study area boundary 773.5 772.5 State Highway 17 771.5 770.5 Observation point 769.5 768.5 767.5 766.5 765.5

Figure 9. Measured and simulated water-surface elevations for the flood of March 20, 2008, on the Gasconade River near Waynesville, Missouri. Two-Dimensional Simulation of Flow 17

-- (ft) 0 -0.06 minus measured Simulated

/s) 3 (ft) 769.09 765.41 762.43 water- surface elevation Simulated (81,600 ft

April 14, 1945, flood -- (ft) 769.15 762.43 water- e surface b elevation Measured

-- 0 (ft) -0.05 minus measured Simulated

/s) 3 (ft) 771.55 768.84 765.80 water- surface elevation Simulated (92,300 ft

December 4, 1982, flood -- (ft) 768.84 765.85 water- d d surface elevation Measured

(ft) -.15 0.17 0 minus measured Simulated

/s) 3 (ft) 772.00 769.20 766.18 water- surface elevation Simulated (95,400 ft

March 20, 2008, flood (ft) 771.83 769.35 766.18 water- a c c surface elevation Measured

Coordinates 37°51’03” N 92°12’52” W 37°51’29” N 92°13’24” W 37°52’24” N 92°13’43” W - Location Measured and simulated water-surface elevations for the calibration floods of March 20, 2008, December 4, 1982, and April 14, 1945, on Gasconade River near Measured and simulated water-surface

Elevation from tape downs from reference point on downstream bridge handrail on the ascending limb of flood near peak April 14, 1945. from reference point on downstream from tape downs Elevation for the 1982 flood. of high water points indicated by local residents to be the approximate level from surveyed Elevation Elevation from tape downs from reference point on downstream bridge handrail on the receding limb of flood near peak March 20, 2008. from reference point on downstream from tape downs Elevation after the flood. marks recovered high-water from surveyed Elevation after the flood. marks recovered of high-water elevation for the peak on April 14, 1945, based average recorded at the gage Elevation a b c d e bridge ville streamflow gaging station gaging ville streamflow /s, cubic feet per second; ft, feet; --, not measured or computed] 3 Downstream handrail of State Highway 17 handrail of State Highway Downstream Near abandoned rental house Near log cabin (near location of Waynes Table 7. Table 88). Datum of 1988 (NAVD Missouri. Elevation referenced to North American Vertical Waynesville, [ft 18 Two-Dimensional Simulation of Flow at State Highway 17 near Waynesville, Missouri

92°13'10" 92°13' 92°12'50"

770.0

770.5

37°51'10"

771.0

771.5

State Highway 17 770.0 772.0

13 773.0 772.5 770.5 12 Water-surface elevation 11 Point Measured Simulated 10 number (feet) (feet) 771.0 9 5 771.5 771.5 1 772.68 772.60 6 7 8 771.0 4 2 772.82 772.66 1 3 3 772.67 772.74 37°51' 772.0 2 772.0 4 772.79 772.88 772.5 5 772.60 772.56 State Highway 17 772.5 6 771.04 770.80 773.0 7 770.96 770.78 8 770.83 770.72 9 771.39 771.33 10 771.35 771.36 11 771.31 771.34 12 771.19 771.48 13 a771.83 772.00 aElevation from tape down from bridge handrail during receding limb of flood.

Base from National Agricultural Imagery Program, 2006 0 200 400 600 800 FEET Universal Transverse Mercator projection, Zone 15 Horizontal coordinate information referenced to the North American Datum of 1983 (NAD 83) 0 50 100 150 200 250 METERS

EXPLANATION Simulated water-surface elevation, in feet above NAVD 88 774.5 Study area boundary 773.5 1 Measurement point 772.5 771.5 770.5 769.5

Figure 10. Measured and simulated water-surface elevations in the vicinity of State Highway 17 for the flood of March 20, 2008, on the Gasconade River near Waynesville, Missouri.

Approximately 1,350 ft downstream from State High- operation during the 1982 flood, a discharge for that event was way 17 and approximately 150 ft upstream from where the estimated from surveyed high-water marks in the vicinity of total discharge measurement was obtained, high left flood State Highway 17 and the Waynesville gage. plain ground elevations on the inside of a bend create a local For the 1982 flood, the total estimated discharge at valley constriction (fig. 11). Simulated results from a flux the Waynesville gage was 92,300 ft3/s. The discharge at the line created at this constriction (fig. 11) indicates the cross- upstream boundary on the Gasconade River in the model of sectional flow area at the constriction (16,030 ft2) is less than existing conditions was set to 87,850 ft3/s, and the upstream the total flow area of the three bridges (20,281 ft2, table 9), boundary on Roubidoux Creek was set to 4,450 ft3/s, based on and the average velocity in this section [5.49 feet per second the ratio of flow observed in the flood of March 2008 (approx- (ft/s)] is higher than any of the three existing bridges (table imately 4.8 percent of the flow was on Roubidoux Creek). The 9). This local constriction likely is a feature that controls flow downstream boundary was set to 765.2 ft to obtain a match characteristics upstream, and may affect flow velocities and with the surveyed high-water marks at the log cabin near the water-surface elevations upstream through the bridge openings Waynesville gage. during major floods. Using the material properties shown in table 6, the water- surface elevations in the model matched the observed water- Flood of December 4, 1982 surface elevations based on the surveyed high-water marks. Measured and simulated water-surface elevations for the 1982 The flood of December 1982 was considered the flood flood are shown in figure 15 and table 7. Other simulated of record for the Gasconade River Basin up until the flood results for the three bridges are shown in table 9. of March 2008. Although the Waynesville gage was not in Two-Dimensional Simulation of Flow 19

92°13'15" 92°13'10" 92°13'05" 92°13'

Measured or simulated Study area velocity, in feet per second boundary 10.5 9.0 7.5 6.0 4.5 3.0 1.5 0 (Measured velocity vectors originate at ship track)

37°51'10" Ship track followed during one of four measurement sections (representative of all four)

Flux line representing measurement sections in the model of existing Flux line at the location of conditions the valley constriction downstream from State Highway 17 in the model of existing conditions 37°51'05"

Base from National Agricultural Imagery Program, 2006 0 100 200 300 400 FEET Universal Transverse Mercator projection, Zone 15 Horizontal coordinate information referenced to the North American Datum of 1983 (NAD 83) 0 25 50 75 100 METERS

Figure 11. Measured and simulated velocity vectors in the vicinity of the measurement section downstream from State Highway 17 for the flood of March 20, 2008, on the Gasconade River near Waynesville, Missouri.

Table 8. Measured and simulated discharge at the main measurement section and locations downstream from structures J-802, K-112, and K-113 for the calibration flood of March 20, 2008, on the Gasconade River near Waynesville, Missouri.

[ft3/s, cubic feet per second]

Measured Simulated Percent Location discharge discharge difference from (ft3/s) (ft3/s) measured Measurement section (ship track on a95,359 93,650 -1.8 fig. 11) Structure J-802 (main channel 49,677 50,067 0.8 bridge, ship track on fig. 12) Structure K-112 (left overflow 12,205 11,821 -3.1 bridge, ship track on fig. 13) Structure K-113 (middle overflow 20,376 22,456 10.2 bridge, ship track on fig. 14) a Measured discharge is the average of four individual measurement sections or “passes” across the flood plain. The ship track shown in figure 11 is from one of the measurement sections that is representative of all four. 20 Two-Dimensional Simulation of Flow at State Highway 17 near Waynesville, Missouri

92°12'53" 92°12'52" 92°12'51" 92°12'50" 92°12'49"

Ship track followed during measurement

37°51'04"

Disabled elements used to represent bridge pier columns

Main channel structure J-802

37°51'03" Measured or simulated velocity, in feet per Disabled elements second used to represent 10.5 bridge pier columns 9.0 7.5 6.0 4.5 3.0 1.5 0 (Measured velocity vectors 37°51'02" originate at ship track)

Base from National Agricultural Imagery Program, 2006 0 25 50 75 100 FEET Universal Transverse Mercator projection, Zone 15 Horizontal coordinate information referenced to the North American Datum of 1983 (NAD 83) 0 10 20 30 METERS

Figure 12. Measured and simulated velocity vectors in the vicinity of main channel structure J-802 on State Highway 17 for the flood of March 20, 2008, on the Gasconade River near Waynesville, Missouri.

92°13'13" 92°13'12" 92°13'11" 92°13'10" 92°13'09" 92°13'08"

Measured or simulated velocity, in feet per second 10.5 9.0 7.5 37°51'01" 6.0 Ship track Approximate flow 4.5 followed direction measured 3.0 during at this location 1.5 measurement 0 (Measured velocity vectors originate at ship track)

37°51' Left overflow structure K-112

Approximate flow direction measured Approximate flow at this location direction measured Bridge bent at this location Approximate flow column locations direction measured as coded in at this location pier module 37°50'59"

Figure 13. Measured and simulated velocity vectors in the vicinity of left overflow structure K-112 on State Highway 17 for the flood of March 20, 2008, on the Gasconade River near Waynesville, Missouri. Two-Dimensional Simulation of Flow 21

92°13'03" 92°13'02" 92°13'01" 92°13' 92°12'59" 92°12'58"

Measured or simulated velocity, in feet per second 10.5 9.0 Ship track 7.5 followed 6.0 during 4.5 Approximate flow measurement 37°51'01" 3.0 1.5 direction measured 0 at this location (Measured velocity vectors originate at ship track)

37°51' Middle overflow structure K-113 Approximate flow direction measured at this location

Bridge bent column locations Approximate flow Approximate flow as coded in direction measured direction measured pier module at this location at this location

37°50'59"

Figure 14. Measured and simulated velocity vectors in the vicinity of middle overflow structure K-113 on State Highway 17 for the flood of March 20, 2008, on the Gasconade River near Waynesville, Missouri.

Flood of April 14, 1945 flood are shown in figure 16 and table 7. Other simulated results for the three bridges are shown in table 9. The flood of April 14, 1945 is the flood of record for the period of continuous streamflow record at the Waynesville gage. A discharge measurement was made at the State High- Simulation of Design Floods way 17 bridge just before the peak on April 14, and the peak discharge at the gage was determined based on that measure- The MoDOT uses several flood recurrence intervals in ment adjusted for time of travel and an analysis of high-water the design of bridges over waterways (Missouri Department marks at the gage. This flood was used as the primary calibra- of Transportation, 2004). In consultation with MoDOT, the tion flood until the flood event of March 20, 2008. It became a 25-year, 50-year, 100-year, and 500-year floods were simu- secondary calibration flood after the model of existing condi- lated for the hydraulic analysis of the State Highway 17 cross- tions had been calibrated to the flood of March 20, 2008. ing. For the 1945 flood, the peak discharge at the Waynesville The discharges and corresponding water-surface eleva- gage was 81,600 ft3/s. The discharge at the upstream bound- tions at the Waynesville gage for the desired recurrence- ary on the Gasconade River was set to 77,670 ft3/s, and the interval floods are shown in table 5. For each flood recurrence upstream boundary on Roubidoux Creek was set to 3,930 interval, the upstream boundary condition on Roubidoux ft3/s, based on the ratio of flow observed in the flood of March Creek was set to 4.8 percent of the full discharge, based on 2008 (approximately 4.8 percent of the flow was on Roubid- the ratio of flow observed in the flood of March 2008, and the oux Creek). The downstream boundary was set to 761.9 ft to balance of the discharge was assigned to the upstream bound- obtain a match with the peak stage recorded at the Waynesville ary on the Gasconade River, as shown in table 5. The down- gage. The peak water-surface elevation at State Highway 17 stream boundary condition was adjusted until the simulated was estimated from stage measurements made there during the water-surface elevation at the Waynesville gage matched the discharge measurement, just before the peak at that location. water-surface elevation from the stage-discharge relation; the Using the material properties shown in table 6, the final value for the downstream boundary condition is shown in water-surface elevations in the model matched the observed table 5. Simulated results for the three bridges for the various water-surface elevations based on the gaging station record. design floods from the model of existing conditions are shown Measured and simulated water-surface elevations for the 1945 in table 9. 22 Two-Dimensional Simulation of Flow at State Highway 17 near Waynesville, Missouri -

------4.79 5.37 5.87 5.98 5.76 6.19 6.87 7.44 8.05 7.31 5.27 5.51 5.79 6.37 5.73 (ft/s) velocity ed average Area-weight

) 2 ------(ft area Cross- 1,466 1,745 2,004 2,638 1,944 2,416 2,801 3,152 3,956 3,061 9,523 10,288 10,969 12,472 10,795 sectional

------of 9.7 total Left overflow structure 11.0 11.9 12.1 11.7 20.8 22.6 23.7 24.5 23.5 69.6 66.5 64.3 61.1 64.8 Main channel structure Percent Middle overflow structure Model of proposed conditions Discharge /s) 3 ------7,020 9,373 (ft 11,764 15,786 11,188 14,967 19,241 23,436 31,858 22,381 50,148 56,719 63,500 79,471 61,832 Through b structure -

3.23 3.68 3.86 4.32 3.97 3.89 3.70 4.07 4.66 5.08 5.65 4.99 4.90 4.91 4.55 4.69 4.89 5.28 4.83 4.79 5.10 (ft/s) velocity ed average Area-weight

) 2 (ft area 3,526 4,181 5,333 3,894 3,772 2,999 4,009 4,567 5,086 6,315 4,962 4,831 3,890 3,005 Cross- 10,126 10,875 11,594 13,148 11,425 11,249 10,092 sectional

of total 15.2 16.4 17.7 16.2 15.9 13.6 22.6 24.9 26.2 27.4 25.9 25.6 23.4 63.8 59.8 57.4 53.4 57.8 58.4 63.1 13.5 Percent Model of existing conditions Left overflow structure (K-112) Main channel structure (J-802) Middle overflow structure (K-113) Discharge /s) 3 9,705 (ft 12,990 16,141 23,029 15,477 14,689 11,086 16,315 21,268 25,860 35,674 24,745 23,659 19,088 51,020 56,663 69,390 55,130 53,913 51,468 46,026 a c c Through structure

/s of flow over the road embankments near the left overflow structure. the road embankments near left overflow over /s of flow /s of flow over the road embankment between structures J-802 and K-113. over /s of flow 3 3

/s of flow over the road embankments near structure K-112. over /s of flow 3 /s) 3 total (ft Flood 85,300 98,700 95,400 92,300 81,600 72,100 85,300 98,700 95,400 92,300 81,600 85,300 98,700 95,400 92,300 81,600 72,100 72,100 130,000 130,000 130,000 , square feet; ft/s, feet per second; --, not determined] 2 Simulated discharge, cross-sectional area, and area-weighted average velocity through the main two overflow structures of S tate Highway 17 for various

Flood event The 500-year flood resulted in 2,802 ft The 500-year flood resulted in 168 ft The 500-year flood resulted in 1,525 ft a b c /s, cubic feet per second; ft 3 50-year flood 100-year flood 500-year flood March 20, 2008 flood December 4, 1982 flood April 14, 1945 flood 25-year flood 50-year flood 100-year flood 500-year flood March 20, 2008 flood December 4, 1982 flood April 14, 1945 flood 50-year flood 100-year flood 500-year flood March 20, 2008 flood December 4, 1982 flood April 14, 1945 flood 25-year flood 25-year flood Table 9. Table Missouri. design flows and the floods of March 20, 2008, December 4, 1982, April 14, 1945, on Gasconade River near Waynesville, [ft Two-Dimensional Simulation of Flow 23

92°14’ 92°13' 92°12'

GASCONADE RIVER Measured, 765.85 ft Simulated, 765.80 ft

765.5

766.0

766.5

37°52' 767.0 767.5

768.0

768.5

Measured, 768.84 ft Simulated, 768.84 ft

769.0

770.0 769.5 770.5 771.0 771.5 772.0 GASCONADE RIVER

37°51' 772.5 773.0

773.5

Base from National Agricultural Imagery Program, 2006 0 1,000 2,000 3,000 4,000 FEET Universal Transverse Mercator projection, Zone 15 Horizontal coordinate information referenced to the North American Datum of 1983 (NAD 83) 0 250 500 750 1,000 METERS EXPLANATION Simulated water-surface elevation, in feet above NAVD 88 774.0 Study area boundary 773.0 772.0 State Highway 17 771.0 770.0 Observation point 769.0 768.0 767.0 766.0 765.0

Figure 15. Measured and simulated water-surface elevations for the flood of December 4, 1982, on the Gasconade River near Waynesville, Missouri. 24 Two-Dimensional Simulation of Flow at State Highway 17 near Waynesville, Missouri

92°14’ 92°13' 92°12'

GASCONADE RIVER

Measured, 762.43 ft Simulated, 762.43 ft

762.0

762.5

763.0

37°52' 763.5

764.0

764.5

765.0

765.5

766.0 766.5 767.0 767.5 768.0 768.5 769.0 769.5 GASCONADE RIVER Measured, 769.15 ft 37°51' Simulated, 769.09 ft 771.0 770.0

771.5 770.5

770.5

Base from National Agricultural Imagery Program, 2006 0 1,000 2,000 3,000 4,000 FEET Universal Transverse Mercator projection, Zone 15 Horizontal coordinate information referenced to the North American Datum of 1983 (NAD 83) 0 250 500 750 1,000 METERS EXPLANATION Simulated water-surface elevation, in feet above NAVD 88 772.5 Study area boundary 771.5 770.5 State Highway 17 769.5 768.5 Observation point 767.5 766.5 765.5 764.5 763.5 762.5 761.5

Figure 16. Measured and simulated water-surface elevations for the flood of April 14, 1945, on the Gasconade River near Waynesville, Missouri. Two-Dimensional Simulation of Flow 25

Preliminary Evaluation of Proposed Model Modifications Modifications The preliminary proposed design of the State Highway After the initial calibration to the 1945 flood, simulations 17 crossing is shown in figure 17A, and elevation data from of two preliminary scenarios for the proposed modifications to the model of proposed conditions is shown in figure 17B. The proposed replacement structure over the main channel will the State Highway 17 crossing were done based on informa- be slightly downstream and angled to the existing structure tion provided by MoDOT using the boundary conditions from J-802. State Highway 17 will be straightened from the exist- the initial calibration to the 1945 flood. This was a conceptual, ing roadway, which will permit construction of the replace- qualitative analysis used by MoDOT to determine the effects ment overflow structures upstream and downstream from the of the overflow structures on velocities and water-surface existing structures to occur with minimal disruption to traffic. elevations in the vicinity of State Highway 17 and water- The existing roadway is approximately level at an elevation of surface elevations upstream. The discussion of the results from 772.00 ft, whereas the proposed roadway will be slightly ele- these preliminary evaluations is qualitative because the initial vated between the main channel bridge and the middle over- calibration to the April 1945 flood was superseded by the later flow bridge. The main channel structure will be 490 ft long, calibration to the March 20, 2008, flood. Although the model consisting of two 125-ft main spans and two 120-ft approach of existing conditions was recalibrated to the April 1945 flood spans supported by concrete bents with dual 3.5-ft diameter as part of the later calibration, there was enough change to the circular columns. The left overflow structure will be 199 ft model to render the specific results of the initial calibration long, consisting of a 71-ft main span and two 64-ft approach imprecise. spans supported by concrete bents with dual 3.5-ft diameter One preliminary scenario involved removing the over- circular columns. The middle overflow structure will be 267 ft flow structures at the State Highway 17 crossing. Based on long, consisting of a 93-ft main span and two 87-ft approach discussions with MoDOT (Keith Ferrell, oral commun., 2008), spans supported by concrete bents with dual 3.5-ft diameter the elements representing the flow through the overflow circular columns. The existing roadway upstream from the structures were disabled in the model of existing conditions, proposed realignment will be left in place and rounded to help effectively creating a solid road embankment without bridges. guide flow into the middle overflow bridge and the main chan- The model of existing conditions was run with the disabled nel bridge (fig. 17B). A short guide bank is proposed upstream elements, which resulted in increased velocity in the main from the right end of the left overflow structure to guide flow into that structure as well (fig. 17B). channel through and downstream from the main bridge (up to The bents for all of the proposed structures were incorpo- 7 ft/s) and a substantial increase (about 2 ft) in the water level rated into the model mesh using the pier module in Flo2DH. upstream from State Highway 17. Because of their small size and circular cross section, these The other preliminary scenario involved using smaller bents would not substantially affect flow in the model, and overflow structures at the State Highway 17 crossing. Based would have resulted in inordinate mesh refinement to incor- on discussions with MoDOT (Keith Ferrell, oral commun., porate directly into the model mesh as disabled elements, as 2008), the elements representing the flow through the overflow had been done for the main channel structure piers and bents structures were limited to a width of about 90 ft. The model in the model of existing conditions. Position, orientation, of existing conditions was run with the narrower overflow and dimensions of each bent were obtained from preliminary structures, which resulted in velocities in the main chan- bridge plans (David Stevenson, written comm., 2008) to accu- nel through and downstream from the main bridge that were rately position and size the bents. Each column of the bents nearly equal to the existing conditions that were simulated in of the proposed replacement structures was coded as round the initial calibration to the 1945 flood, and a smaller increase 3.5-ft diameter columns in the pier module, as noted from the (approximately 0.75 ft) in the water level upstream from State preliminary bridge plans. Highway 17; however, the velocities through the narrower Material and hydraulic properties developed in the model overflow structures were substantially greater than the existing of existing conditions were used in the model of proposed conditions (more than 12 ft/s). conditions, and all new mesh elements were assigned values consistent with the model of existing conditions, based on the proposed land use in the model of proposed conditions (fig. Model of Proposed Conditions 18; table 6). All the proposed modifications, such as clear- ing of trees, road realignment, and new structures, will occur While the design floods were being simulated in the in the vicinity of State Highway 17; therefore, most of the model of existing conditions, MoDOT developed prelimi- modified elements were assigned the “highway embankment” nary plans for the proposed replacement structures for J-802, material properties. K-112, and K-113. These preliminary plans were used to The finite-element mesh for the model of proposed condi- develop a model of proposed conditions to simulate the design tions consisted of 25,906 elements that ranged in size from floods for comparison to the existing conditions. 2.43 to 10,295 ft2. Each element had a node at each corner and 26 Two-Dimensional Simulation of Flow at State Highway 17 near Waynesville, Missouri

92°13'10" 92°13' 92°12'50"

37°51'10" Study area boundary

Proposed Proposed main channel realignment structure Proposed Existing Existing middle overflow main channel left overflow structure structure, J-802, structure, K-112, to be removed to be removed 37°51' Existing Existing State Highway 17 Proposed middle overflow left overflow structure, K-113, structure to be removed

B Rendered ground elevation, in feet above NAVD 88 Study area boundary 37°51'10" (shading added) 820 810 800 790 780 770 760 750 Proposed 740 main channel 730 structure

Existing Proposed Existing left overflow middle overflow main channel structure, K-112, structure structure, J-802, removed removed 37°51' Existing Existing State Highway 17 middle overflow embankment, left in structure, K-113, place and rounded Proposed Existing Guidebank removed to guide flow left overflow added to State Highway 17 structure guide flow embankment, left in place and rounded to guide flow

Figure 17. Preliminary proposed alignment of State Highway 17 over the Gasconade River near Waynesville, Missouri, A, in relation to the existing conditions and B, as rendered with shaded ground elevation data in the model of proposed conditions. Two-Dimensional Simulation of Flow 27

92°13'10" 92°13' 92°12'50"

A 37°51'10"

37°51'

B 37°51'10"

37°51'

EXPLANATION

Land Use Sand and gravel channel Thick timber and thick brush Highway embankment Row crops (corn) Open timber and brush Pavement and gravel Pasture Thick grasses with sprouts Bridge deck

Study area boundary/area of no flow Figure 18. Land-use coverages in the vicinity of State Highway 17 used in A, the model of existing conditions and B, the model of proposed conditions on the Gasconade River near Waynesville, Missouri. 28 Two-Dimensional Simulation of Flow at State Highway 17 near Waynesville, Missouri at the midpoint of each side, which created a total of 58,291 20, 2008, as well as the 25-, 50-, 100-, and 500-year floods nodes. are shown in figures 21 through 25. Generally, the simulated water-surface elevations from the model of proposed conditions are slightly greater upstream from the State Highway 17 Simulation of Design Floods crossing than from the model of existing conditions in all of As with the model of existing conditions, simulations the flow scenarios examined. of the 25-, 50-, 100-, and 500-year recurrence-interval floods Because the model mesh was different between the model were conducted, as well as the flood of March 20, 2008. For of existing conditions and the model of proposed conditions, a each flood, the upstream boundary conditions on the Gas- direct, node-by-node comparison of results from the two mod- conade River and Roubidoux Creek were set to the discharge els was not possible; however, the SMS package allows the values from table 5, and the downstream boundary was set user to create observation profile lines in a model, from which to the water-surface elevation determined from the model of model results can be extracted. Four observation profile lines existing conditions shown in table 5. Simulated results for the were created (fig. 26) in the model of existing conditions and three bridges for the various design floods from the model of the model of proposed conditions. One line was drawn along proposed conditions are shown in table 9. the centerline of the Gasconade River main channel from the Based on the simulated results for the flood of March 20, upstream boundary of the model to a point approximately 2008, the proposed structures have a total cross-sectional flow 2,300 ft downstream from the existing main channel structure area (15,800 ft2) that is slightly smaller than the flow area of J-802. Another line was drawn parallel to flow on the right the downstream valley constriction (16,030 ft2) as determined flood plain upstream from the State Highway 17 crossing. Two in the model of existing conditions. The downstream constric- additional lines were drawn through the left and middle over- tion may continue to act as a flow control feature to upstream flow structures from a point upstream from State Highway 17 flow velocities and water-surface elevations in major floods, on the main channel observation line to the downstream end of but the smaller area of the proposed structures will cause them the main channel line downstream from State Highway 17 (fig. to act as flow control features to areas upstream from them- 26). Data from the observation lines could be extracted from selves. the models for the various flow simulations and compared. The water-surface elevation departure of the proposed conditions from the existing conditions along the main channel Effect of Proposed Changes is shown in figure 27, and the velocity magnitude departure of the proposed conditions from the existing conditions is The effects of the proposed road alignment and bridge shown in figure 28. The maximum water-surface elevation replacements are of critical interest to MoDOT (Missouri departure ranges from approximately 0.18 ft for the 25-year Department of Transportation, 2004). An increase in velocity flood (increase in depth from 27.58 ft to 27.76 ft) to 0.32 ft for in the main channel could result in damaging stream bed and the 500-year flood (increase in depth from 33.79 ft to 34.11 bank erosion in the channel as well as scour near the bridge ft), and occurs approximately midway between the upstream piers, and an increase in depth of flow upstream from State boundary of the model and the main channel structure on State Highway 17 could result in more inundated area, which, in Highway 17. The smaller overflow structures in the model turn, creates more flooding for upstream property. of proposed conditions cause this increase in water-surface The existing roadway upstream from the proposed elevation upstream from State Highway 17, with a commensu- realignment will be left in place and rounded to help guide rate decrease in velocity magnitude. There is a decrease in the flow into the middle overflow bridge and the main channel water-surface elevations downstream from State Highway 17, bridge (fig. 17). A short guidebank is proposed upstream from with a commensurate increase in velocity in this reach (figs. the right end of the left overflow structure to guide flow into 27 and 28). The maximum departure in velocity magnitude that structure as well (fig. 17). Model simulations indicate that is approximately 1.2 ft/s, and occurs approximately 1,500 ft the 100- and 500-year floods partially or completely inundate downstream from the main channel structure, near the location the existing road embankments in the model of proposed of the downstream valley constriction (fig. 28). Downstream conditions, resulting in shallow, high-velocity flow at the from the main channel structure, the magnitude of the depar- upstream edges of the abutments of the overflow structures ture in water-surface elevation does not increase with increas- (fig. 19); however, model simulations indicate that the existing ing discharge, as it does upstream from the main channel road embankments are not inundated by the 25- or the 50-year structure (fig. 27); the flood of March 20, 2008, has the largest floods in the model of proposed conditions, and the embank- departure, whereas the departures of the 100- and 500-year ments effectively guide flow through the bridges (fig. 20). A floods are similar to the departure of the 50-year flood. It higher embankment at the bridge openings would guide flow should be noted that the maximum departure downstream from through the bridges at higher flows. the main channel structure is approximately -0.11 ft. The simulated water-surface elevations from the model For the left (west) overflow structure, the water-surface of existing conditions and the model of proposed conditions elevation departure of the proposed conditions from the exist- in the vicinity of State Highway 17 for the flood of March ing conditions is shown in figure 29, and the velocity magni- Two-Dimensional Simulation of Flow 29

92°13'10" 92°13' 92°12'50"

37°51'10"

State Highway 17

Proposed alignment

37°51' Proposed alignment

Proposed alignment

37°51'10"

State Highway 17

Proposed alignment

37°51'

Proposed alignment

EXPLANATION Velocity magnitude, in feet per second Study area boundary

0.0 1.5 3.0 4.5 6.0 7.5 9.0 10.5 12.0 13.5 15.0

Figure 19. Simulated velocity magnitudes in the vicinity of State Highway 17 from the model of proposed conditions for the A, 100-year and B, 500-year floods on the Gasconade River near Waynesville, Missouri. 30 Two-Dimensional Simulation of Flow at State Highway 17 near Waynesville, Missouri

92°13'10" 92°13' 92°12'50"

37°51'10"

State Highway 17

Proposed alignment

37°51' Proposed alignment

Proposed alignment

37°51'10"

State Highway 17

Proposed alignment

37°51' Proposed alignment

Proposed alignment

EXPLANATION Velocity magnitude, in feet per second Study area boundary

0.0 1.5 3.0 4.5 6.0 7.5 9.0 10.5 12.0 13.5 15.0

Figure 20. Simulated velocity magnitudes in the vicinity of State Highway 17 from the model of proposed conditions for the A, 25-year and B, 50-year floods on the Gasconade River near Waynesville, Missouri. Two-Dimensional Simulation of Flow 31

92°13'10" 92°13' 92°12'50"

A 770.0 770.5

37°51'10"

771.0

771.5

State Highway 17 770.0 772.0

773.0 772.5 770.5

771.0 771.5 771.5 771.0

37°51' 772.0 772.0 772.5 State Highway 17 772.5 773.0

B 770.0

770.5 37°51'10"

771.0

771.5

772.0 State Highway 17 770.0 772.5

773.0

771.0 770.5 Proposed alignment 770.5 771.5 771.0 772.0 771.0 37°51' 772.5 771.5 Proposed alignment 772.0 772.5 Proposed alignment 773.0 773.0

773.5

EXPLANATION Simulated water-surface elevation, in feet above NAVD 88 Study area boundary

769.5770.0770.5 771.0771.5772.0 772.5 773.0773.5774.0 774.5

Figure 21. Simulated water-surface elevations in the vicinity of State Highway 17 for the flood of March 20, 2008 from A, the model of existing conditions and B, the model of proposed conditions on the Gasconade River near Waynesville, Missouri. 32 Two-Dimensional Simulation of Flow at State Highway 17 near Waynesville, Missouri

92°13'10" 92°13' 92°12'50"

767.0

A 767.5

37°51'10" 768.0

768.5

769.0

767.0 State Highway 17 767.5

769.5 770.0

768.0

769.0 768.5 768.5 37°51' 769.5 769.0 769.5 State Highway 17 770.0 770.0

770.5

767.0

B 767.5

37°51'10" 768.0

768.5

769.0 State Highway 17 767.0 767.5 769.5

770.0

768.0 768.0 768.5 Proposed alignment 769.0 769.5 768.5 37°51' 770.0 Proposed alignment 769.0

Proposed alignment 770.0 770.5

EXPLANATION Simulated water-surface elevation, in feet above NAVD 88 Study area boundary

766.5767.0767.5768.0768.5769.0769.5770.0770.5771.0771.5772.0

Figure 22. Simulated water-surface elevations in the vicinity of State Highway 17 for the 25-year flood from A, the model of existing conditions and B, the model of proposed conditions on the Gasconade River near Waynesville, Missouri. Two-Dimensional Simulation of Flow 33

92°13'10" 92°13' 92°12'50"

769.0 A

769.5 37°51'10" 768.5

770.0

770.5

State Highway 17 769.0 771.0

771.5

769.5 770.0 770.5

770.0 37°51' 771.0 770.5 771.0 771.5 State Highway 17 771.5

772.0

769.0 B

769.5 37°51'10" 768.5

770.0

770.5

State Highway 17 769.0 771.0 771.5

772.0

769.5 770.0 Proposed alignment

769.5 770.0 771.0770.5 769.5 37°51' 771.5 Proposed alignment 770.5 772.0 771.5 Proposed alignment 772.0

772.5

EXPLANATION Simulated water-surface elevation, in feet above NAVD 88 Study area boundary

768.0768.5769.0769.5770.0770.5771.0771.5772.0772.5773.0773.5774.0

Figure 23. Simulated water-surface elevations in the vicinity of State Highway 17 for the 50-year flood from A, the model of existing conditions and B, the model of proposed conditions on the Gasconade River near Waynesville, Missouri. 34 Two-Dimensional Simulation of Flow at State Highway 17 near Waynesville, Missouri

92°13'10" 92°13' 92°12'50"

770.5 A

771.0

37°51'10" 770.0

771.5

772.0

State Highway 17 770.5 772.5 773.0

771.0 771.5 772.0

771.5 37°51' 772.5 772.0 772.5 State Highway 17 773.0 773.0

773.5

770.5 B

37°51'10" 771.0

771.5

772.0 State Highway 17 772.5 770.5 773.0

773.5 771.0

771.5 771.5 771.0 Proposed alignment 772.0 772.5 37°51' 773.0 Proposed alignment 772.0 773.5 773.0 Proposed alignment 773.5

774.0

EXPLANATION Simulated water-surface elevation, in feet above NAVD 88 Study area boundary

769.5770.0770.5771.0771.5772.0772.5773.0773.5774.0774.5775.0

Figure 24. Simulated water-surface elevations in the vicinity of State Highway 17 for the 100-year flood from A, the model of existing conditions and B, the model of proposed conditions on the Gasconade River near Waynesville, Missouri. Two-Dimensional Simulation of Flow 35

92°13'10" 92°13' 92°12'50"

773.5 A 774.0

37°51'10"

774.5

775.0

State Highway 17 775.5 773.5 776.0

776.5

774.0 774.5 775.0 775.0 775.5 774.5 37°51' 776.0 775.5 State Highway 17 776.0 776.5

B 773.5

774.0

37°51'10"

774.5

775.0 777.0

775.5 State Highway 17

776.0 776.5 773.5

774.5 774.0 774.5 Proposed alignment 775.0 774.5 775.5 775.0 37°51' 776.0 774.0 Proposed alignment 775.5 776.5 776.0 Proposed alignment 776.5 776.5

777.0

EXPLANATION Simulated water-surface elevation, in feet above NAVD 88 Study area boundary

773.0773.5774.0774.5775.0775.5776.0776.5777.0777.5778.0

Figure 25. Simulated water-surface elevations in the vicinity of State Highway 17 for the 500-year flood from A, the model of existing conditions and B, the model of proposed conditions on the Gasconade River near Waynesville, Missouri. 36 Two-Dimensional Simulation of Flow at State Highway 17 near Waynesville, Missouri

92°13'30" 92°13'20" 92°13'10" 92°13' 92°12'50" 92°12'40"

37°51'10"

Highway 17 State Main channel 1 State High structure way 17

3 37°51' Middle 4 Left overflow overflow structure Right structure flood plain 2

37°50'50"

EXPLANATION Study area boundary 1 Observation profile line—Node indicates “zero” reference

Figure 26. Arcs used as observation profile lines in the vicinity of State Highway 17 on the Gasconade River near Waynesville, Missouri. tude departure of the proposed conditions from the existing ture in the proposed conditions once again causes an increase conditions is shown in figure 30. The maximum water-surface in the velocity (approximately 2.15 ft/s on the observation elevation departure occurs downstream from the new overflow line for the 500-year flood) through the new bridge opening structure, at the location of the existing structure K-112 (fig. (fig. 32), which continues into the flood plain downstream 29). The smaller overflow structure in the proposed conditions from State Highway 17. This increase in velocity magnitude causes a substantial increase in the velocity (approximately results in a commensurate decrease in water-surface elevation 4.9 ft/s on the observation line for the 500-year flood) through (fig. 31). Downstream from State Highway 17, the velocity the new bridge opening (fig. 30), which remains until the magnitudes from the model of proposed conditions are greater downstream face of the existing State Highway 17 embank- than those from the model of existing conditions; however, the ment is reached. This increase in velocity magnitude results in departures are less than for the left overflow structure. a commensurate decrease in water-surface elevation (fig. 29). Whereas the flood of March 20, 2008, and the 25-, 50-, Downstream from State Highway 17, the velocity magnitudes 100-year floods generally display similarly shaped curves in from the model of proposed conditions are less than those figures 27 through 32, the 500-year flood often has a more from the model of existing conditions. unique shape. The difference of the 500-year flood data is For the middle overflow structure, the water-surface ele- most obvious in the velocity magnitude departures (figs. 28, vation departure of the proposed conditions from the existing 30, and 32), but it also is apparent in the water-surface eleva- conditions is shown in figure 31, and the velocity magnitude tion departures for the overflow structures (figs. 29 and 31). departure of the proposed conditions from the existing condi- The unique shape of the 500-year flood data likely is the result tions is shown in figure 32. The maximum water-surface ele- of the flow over State Highway 17 road embankment. In the vation departure occurs approximately 130 ft upstream from 500-year flood scenario, the location of road overflow changes the existing structure K-113 (increase in depth from 19.79 ft to from the embankment between the main channel structure 20.14 ft for the 500-year flood). The smaller overflow struc- J-802 and the middle overflow structure K-113 in the model of Two-Dimensional Simulation of Flow 37

0.35 Existing structure J-802 Proposed main channel structure 0.30

Channel Right 0.25 centerline, flood plain, observation observation line 1 line 2 0.20 500 year 100 year March 2008 0.15 50 year 25 year 0.10

0.05

Proposed conditions greater than existing conditions 0 Proposed conditions less than existing conditions

-0.05 DEPARTURE FROM EXISTING WATER-SURFACE ELEVATION, IN FEET

-0.10

-0.15 -4,000 -3,500 -3,000 -2,500 -2,000 -1,500 -1,000 -500 0 500 1,000 1,500 2,000 2,500

DISTANCE DOWNSTREAM FROM DOWNSTREAM FACE OF EXISTING MAIN CHANNEL STRUCTURE J-802, IN FEET

Figure 27. Departure of simulated water-surface elevation in the model of proposed conditions from the model of existing conditions along the channel centerline and on the right flood plain upstream from State Highway 17 on the Gasconade River near Waynesville, Missouri.

1.25 Existing structure J-802 Proposed main channel structure Channel Right centerline, flood plain, 1.00 observation observation line 1 line 2 500 year 100 year 0.75 March 2008 50 year 25 year 0.50

0.25

Proposed conditions greater than existing conditions 0

-0.25 Proposed conditions less than existing conditions

-0.50 DEPARTURE FROM EXISTING VELOCITY MAGNITUDE, IN FEET PER SECOND

-0.75 -4,000 -3,500 -3,000 -2,500 -2,000 -1,500 -1,000 -500 0 500 1,000 1,500 2,000 2,500

DISTANCE DOWNSTREAM FROM DOWNSTREAM FACE OF EXISTING MAIN CHANNEL STRUCTURE J-802, IN FEET

Figure 28. Departure of simulated velocity magnitude in the model of proposed conditions from the model of existing conditions along the channel centerline and on the right flood plain upstream from State Highway 17 on the Gasconade River near Waynesville, Missouri. 38 Two-Dimensional Simulation of Flow at State Highway 17 near Waynesville, Missouri

0.4 Proposed left overflow structure Existing structure K-112

0.2

Proposed conditions greater than existing conditions 0 Proposed conditions less than existing conditions

-0.2 Left overflow, observation line 3 500 year -0.4 100 year March 2008 50 year 25 year -0.6

-0.8 DEPARTURE FROM EXISTING WATER-SURFACE ELEVATION, IN FEET

-1.0 -1,500 -1,250 -1,000 -750 -500 -250 0 250 500 750 1,000 1,250 1,500 DISTANCE DOWNSTREAM FROM DOWNSTREAM FACE OF EXISTING LEFT OVERFLOW STRUCTURE K-112, IN FEET

Figure 29. Departure of simulated water-surface elevation in the model of proposed conditions from the model of existing conditions along the observation profile line through the left overflow structure of State Highway 17 on the Gasconade River near Waynesville, Missouri.

5.0

4.5 Proposed left overflow structure Existing structure K-112

4.0

3.5 Left overflow, 3.0 observation line 3 2.5 500 year 2.0 100 year March 2008 1.5 50 year 1.0 25 year 0.5 Proposed conditions greater than existing conditions 0 Proposed conditions less -0.5 than existing conditions -1.0

-1.5

-2.0

-2.5

-3.0 DEPARTURE FROM EXISTING VELOCITY MAGNITUDE, IN FEET PER SECOND -3.5 -4.0 -1,500 -1,250 -1,000 -750 -500 -250 0 250 500 750 1,000 1,250 1,500 DISTANCE DOWNSTREAM FROM DOWNSTREAM FACE OF EXISTING LEFT OVERFLOW STRUCTURE K-112, IN FEET

Figure 30. Departure of simulated velocity magnitude in the model of proposed conditions from the model of existing conditions along the observation profile line through the left overflow structure of State Highway 17 on the Gasconade River near Waynesville, Missouri. Two-Dimensional Simulation of Flow 39

0.40 Existing structure K-113 Proposed middle overflow structure 0.35

0.30 Middle overflow, 0.25 observation line 4 0.20 500 year 100 year 0.15 March 2008 50 year 25 year 0.10

0.05 Proposed conditions greater than existing conditions 0 Proposed conditions less than existing conditions -0.05

-0.10

-0.15 DEPARTURE FROM EXISTING WATER-SURFACE ELEVATION, IN FEET -0.20

-0.25 -800 -600 -400 -200 0 200 400 600 800 1,000 1,200 1,400 1,600 1,800 DISTANCE DOWNSTREAM FROM DOWNSTREAM FACE OF EXISTING MIDDLE OVERFLOW STRUCTURE K-113, IN FEET

Figure 31. Departure of simulated water-surface elevation in the model of proposed conditions from the model of existing conditions along the observation profile line through the middle overflow structure of State Highway 17 on the Gasconade River near Waynesville, Missouri.

2.50 Existing structure K-113 Proposed middle overflow structure 2.25

2.00 Middle overflow, 1.75 observation line 4 1.50 500 year 100 year 1.25 March 2008 50 year 1.00 25 year

0.75

0.50 Proposed conditions greater 0.25 than existing conditions

-0.25 Proposed conditions less

DEPARTURE FROM EXISTING VELOCITY MAGNITUDE, IN FEET PER SECOND -0.50 than existing conditions

-0.75 -800 -600 -400 -200 0 200 400 600 800 1,000 1,200 1,400 1,600 1,800

DISTANCE DOWNSTREAM FROM DOWNSTREAM FACE OF EXISTING MIDDLE OVERFLOW STRUCTURE K-113, IN FEET

Figure 32. Departure of simulated velocity magnitude in the model of proposed conditions from the model of existing conditions along the observation profile line through the middle overflow structure of State Highway 17 on the Gasconade River near Waynesville, Missouri. 40 Two-Dimensional Simulation of Flow at State Highway 17 near Waynesville, Missouri existing conditions to the embankment between the overflow realignment of State Highway 17 (the “model of proposed structures in the model of proposed conditions (fig. 25). Road conditions”). The models of existing and proposed conditions overflow does not occur in the other flood scenarios (figs. 21 were used to simulate the 25-, 50-, 100-, and 500-year recur- through 24). rence floods, as well as the March 20, 2008 flood. Results from the model of proposed conditions indicate that the proposed replacement structures and realignment of Summary State Highway 17 will result in additional backwater upstream from State Highway 17 ranging from approximately 0.18 Hydrologic and hydraulic parameters were determined foot for the 25-year flood (increase in depth from 27.58 feet for the Gasconade River at the site of a proposed bridge to 27.76 feet) to 0.32 foot for the 500-year flood (increase replacement and highway realignment of State Highway 17 in depth from 33.79 feet to 34.11 feet). Velocity magnitudes near Waynesville, Missouri. Existing main channel structure, in the proposed overflow structures were higher than in the J-802, and two overflow structures, K-112 and K-113, are existing structures [by as much as 4.9 feet per second in the planned to be replaced and the highway realigned to permit left (west) overflow structure for the 500-year flood], and staging of construction of the replacement structures. shallow, high-velocity flow occurs at the upstream edges of Information from a discontinued streamflow-gaging station on the Gasconade River near Waynesville (station number the abutments of the proposed overflow structures in the 100- 06928500, “the Waynesville gage”) was used to determine and 500-year floods where flow overtops parts of the existing streamflow statistics for analysis of the 25-, 50-, 100-, and road embankment that will be left in place in the proposed 500-year floods at the site. Analysis of the streamflow-gaging scenario. Velocity magnitude in the main channel of the model stations on the Gasconade River upstream and downstream of proposed conditions increased by a maximum of 1.2 feet from Waynesville indicate that flood peaks are attenuated per second over the model of existing conditions, with the between the upstream gaging station near Hazelgreen and the maximum occurring approximately 1,500 feet downstream Waynesville gage, so that the peak discharge observed on the from existing main channel structure J-802 near the location of Gasconade River near Waynesville will be equal to or only a valley constriction. slightly greater (7 percent or less) than that observed near Hazelgreen. A peak flood event occurred on the Gasconade River, and a flood measurement was obtained downstream from State References Cited Highway 17 on March 20, 2008, near the time of the peak at that location. The elevation of high-water marks from that Alexander, T.W., and Wilson, G.L., 1995, Technique for esti- event indicated it was the highest measured flood in the history mating the 2- to 500-year flood discharges on unregulated of the Waynesville gage. The measured discharge was 95,400 streams in rural Missouri: U.S. Geological Survey Water- cubic feet per second, with a corresponding water-surface Resources Investigations Report 95–4231, 33 p. elevation of 766.18 feet near the location of the Waynesville gage. The measurements obtained for the March flood resulted Arcement, G.J., Jr., and Schneider, V.R., 1989, Guide for in a shift of the original stage-discharge relation for the selecting Manning’s roughness coefficients for natural chan- Waynesville gage. Furthermore, the streamflow statistics were nels and flood plains: U.S. Geological Survey Water-Supply modified based on the new data. The shifted stage-discharge Paper 2339, 38 p. relation was used to estimate the peak discharges for calibrating the two-dimensional hydraulic models of the State High- Barnes, H.H., Jr., 1967, Roughness characteristics on natu- way 17 crossing, and the modified streamflow statistics were ral channels: U.S. Geological Survey Water-Supply Paper used for the 25-, 50-, 100-, and 500-year floods at the site. 1849, 213 p. A two-dimensional hydrodynamic flow model was used to simulate flow conditions on the Gasconade River in Chow, V.T., 1959, Open-channel hydraulics: St. Louis, Mo., the vicinity of State Highway 17, using the depth-averaged McGraw-Hill Publishing Company, 678 p. Finite Element Surface-Water Modeling System (FESWMS Flo2DH). A model was developed that represents condi- Environmental Modeling Research Laboratory, 1999, Surface- tions as they exist currently (2008) on State Highway 17 water modeling system reference manual, version 8.0: (the “model of existing conditions”). The model of existing Provo, Utah, Brigham Young University, 315 p. conditions was calibrated to the floods of March 20, 2008, December 4, 1982, and April 14, 1945. Modifications were Froehlich, D.C., 2002, Two-dimensional depth-averaged flow made to the model of existing conditions to create a model that and sediment transport model—Users manual for FESWMS represents conditions along the same reach of the Gasconade Flo2DH: Federal Highway Administration, FHWA– River with preliminary proposed replacement bridges and RD–03–053, 203 p. References Cited 41

Huizinga, R.J., 2007a, Two-dimensional hydrodynamic model- Missouri Department of Transportation, 1932c, Bridge over ing and analysis of the proposed channel modifications and Gasconade River overflow: Jefferson City, Missouri State grade control structure on the Blue River near Byram’s Ford Highway Department, Project No. E359C (R17), Bridge Industrial Park, Kansas City, Missouri: U.S. Geological No. K-113. Survey Scientific Investigations Report 2007–5098, 45 p. Missouri Department of Transportation, 2004, Bridge design Huizinga, R.J., 2007b, Two-dimensional simulation of flow and evaluation of bridge scour at structure A-1700 on Inter- manual: Missouri Department of Transportation Bridge state 155 over the Mississippi River near Caruthersville, Division, Sections 8.2, 60 p. Missouri: U.S. Geological Survey Scientific Investigations Missouri Spatial Data Information Service, 2008, Missouri Report 2007–5230, 33 p. Spatial Data Information Service (MSDIS): Columbia, Huizinga, R.J., and Rydlund, P.H., Jr., 2001, Simulation of University of Missouri–Columbia, accessed September 15, flow and evaluation of bridge scour at Horse Island Chute 2008, at http://www.msdis.missouri.edu/index.htm Bridge near Chester, Illinois: U.S. Geological Survey Water- Resources Investigations Report 01–4176, 28 p. National Weather Service, 2008, Archived daily precipitation for Missouri: National Oceanic and Atmospheric Associa- Hydrologic Subcommittee of Interagency Advisory Commit- tee on Water Data, 1982, Guidelines for determining flood tion, National Weather Service, accessed June 19, 2008, at flow frequency (revised): U.S. Geological Survey, Office of http://www.weather.gov/. Water Data Coordination, Bulletin 17B, 28 p., 14 appendi- ces and 1 pl. U.S. Geological Survey, 2008a, 06928000 Gasconade River near Hazelgreen, MO: U.S. Geological Survey Water-Data Missouri Department of Transportation, 1932a, Bridge over Report 2007, accessed June 19, 2008, at http://wdr.water. Gasconade River: Jefferson City, Missouri State Highway usgs.gov/wy2007/pdfs/06928000.2007.pdf Department, Project No. E359C (R17), Bridge No. J-802. U.S. Geological Survey, 2008b, 06933500 Gasconade River Missouri Department of Transportation, 1932b, Bridge over Gasconade River overflow: Jefferson City, Missouri State at Jerome, MO: U.S. Geological Survey Water-Data Report Highway Department, Project No. E359C (R17), Bridge 2007, accessed June 19, 2008, at http://wdr.water.usgs.gov/ No. K-112. wy2007/pdfs/06933500.2007.pdf

U.S. Geological Survey, 2008b, 06933500 Gasconade River at Jerome, MO: U.S. Geological Survey Water- Data Report 2007, http://wdr.water.usgs.gov/wy2007/ pdfs/06933500.2007.pdf, accessed June 19, 2008. 42 Two-Dimensional Simulation of Flow at State Highway 17 near Waynesville, Missouri

Publishing support provided by: Rolla Publishing Service Center

For more information concerning this publication, contact: Director, USGS Missouri Water Science Center 1400 Independence Road Rolla, MO 65401 (573) 308–3667

Or visit the Missouri Water Science Center Web site at: http://mo.water.usgs.gov References Cited 43 Huizinga—Two-Dimensional Simulation of Flow at State Highway 17 near Waynesville, Missouri—Scientific Investigations Report 2008–5194