FLOOD PROFILES IN THE UMPQUA RIVER. BASIN, OREGON PART 3 1

Transcription

1 FLOOD PROFLES N THE UMPQUA RVER. BASN, OREGON PART 3 1-4

2 U-STATES DEPARTMENT OF THE NTEROR teologcal SURVEY FLOOD PROFLES N THE UMPQUA RVER BASN, OREGON By Eugene A. Oster pqua River below Scottsburg. Smith River, Scholfield Creek Cow Creek above Glendale Prepared in cooperation with DOUGLAS COUNTY OPEN-FLE REPORT Portland, Oregon

3 CONTENTS Page ntroduction 1 Study methods 3 Flood-frequency analysis 3 Photogrammetric mapping 5. Collection of field data 6 Step-backwater analysis 7 Tidal reaches 7 Description 7 Umpqua River 7 Scholfield Creek 7 Smith River 7 Floods in the tidal reaches of the Umpqua River basin 8 Flood profiles in the tidal reaches 9 Umpqua River 9 Scholfield Creek 11 Smith River 12 Upper Cow Creek 13 Description of the study reach 13 Floods 13 Flood profiles 13 Use of the results 16 Summary 17 References 17

4 LLUSTRATONS Figure 1. ndex map showing locations of study reaches 2 Page Discharge-frequency curve, Umpqua River below Scottsburg 3 Discharge-frequency curve, Scholfield Creek 4 Discharge-frequency curve, Smith River 4 Discharge-frequency curve, Cow Creek near Aalea 5 Stage-frequency curve, Umpqua River at Reedsport 9 Stage hydrograph, Umpqua River near Elkton, flood of January Stage hydrograph, Cow Creek near Aalea, flood of January Stage-discharge relation, Cow Creek near Aalea Water-surface profiles Cross sections 65 TABLES Page Table 1. Annual peaks for Smith River near Gardiner, Oreg. (gaging station 3231) 18 Annual peaks for Cow Creek near Aalea, Oreg. (gaging station 39) 19 Discharges used to develop the flood profiles 21 Profile elevations for Umpqua River 22 Profile elevations for Scholfield Creek 24 Profile elevations for Smith River 25 Profile elevations for Cow Creek 27

5 FACTORS FOR CONVERTNG FROM ENGLSH TO METRC UNTS For readers who may prefer to use metric units rather than English units, the conversion factors for terms used in this report are listed below. The factors are shown to four significant figures; however, in the text the metric equivalents are shown only to the number of significant figures consistent with the values for the English units. Multiply p1 To obtain feet (ft).348 miles (mi) 1.69 cubic feet per second.2832 (cfs) metres (in) kilometres (kin) cubic metres per second (mis) 111

6 FLOOD PROFLES N THE UVPQUA RVER BASN, OREGON Part 3 By Eugene A. Oster NTRODUCTON The elevations and characteristics of floods are major factors that influence land-use planning of the flood plains of any stream. As the lowlands become more intensively used, a firm basis for assessing the risk of flood damage becomes increasingly important. Land-use oning is not only a legal requirement passed by the Oregon State Legislature in 1969; it is necessary to ensure a use compatible with the risk of flood damage. Profile elevations of floods with a specific recurrence interval are essential to establish land-use one boundaries. This study was made at the request of Douglas County Planning Commission to compute profiles for the 1-, 25-, 1-, and 5-year floods and the December 1964 flood. A profile of the Umpqua River was computed for the 1- year flood adjusted for storage in the proposed Days Creek Lake on the South Umpqua River above Days Creek. Profile elevations were also computed for the 2-year and 5-year floods, and are presented to serve the needs of users other than Douglas County. This report is the third and final in a series to cover approximately 3 miles (48 km) of Umpqua River basin streams. Although the reports are intended as a series, some introductory and explanatory material is repeated in each, so that each report can stand independently. The reaches covered in this report are: Urnpqua River from Gardiner upstream to Scottsburg, Smith River from the mouth to Sulphur Springs, Scholfield Creek from the mouth to Wind Creek, and upper Cow Creek from below Glendale upstream to Snow Creek, near Anchor (fig. 1). The reaches covered in part 2 of this series (Oster, 1973) are: Umpqua River from Scottsburg upstream to Hubbard Creek, and North Umpqua River from Winchester Dam upstream to dleyld Park. The reaches covered by part 1 of this series (Oster, 1972) are: Umpqua River above Hubbard Creek, North Umpqua River below Winchester Dam, and South Umpqua River and parts of selected tributaries below Days Creek.

7 EXPLANAT ON 43a45' Stream-gaging station S39 G LAS NDEX MAP OF OREGON 123 OO,. 1om.T Fgure 1.--ndex map show ng locat ons of study reaches.

8 This report presents the data needed to determine areas subject to inundation by the selected floods. Flooded areas can be determined by transferring the flood-profile elevations and the flooded width shown on the cross sections to the orthophoto work maps. A word of sincere appreciation is due Berl Oar, of Douglas County Water Resources Survey, whose help in locating many high-water marks and bench marks greatly expedited the collection of field data. STUDY METHODS Flood-Frequency Analysis The flood-frequency data needed to determine project discharges were computed by the log-pearson Type method, using annual peak-flow data for Cow Creek and the Umpqua River. A regional analysis by the Corps of Engineers (1969) was used for the Smith River and Scholfield Creek because the streamf low data are inadequate on the Smith River and nonexistent for Scholfield Creek. The frequency curves used are shown in figures C', RECURRENCE NTERVAL, N YEARS Figure 2.--Discharge-frequency curve, Umpqua River below Scottsburg. 3

9 w ) w - w U- U- () U) w C) U) RECURRENCE NTERVAL, N YEARS Figure 3.--Discharge-frequency curve, Scholfield Creek. w U, Q. - w U- D C) U- U) 2 5 Cl) 2 D - 2 w RECURRENCE NTERVAL, N YEARS Figure 4.--Discharge-frequency curve, Smith River. 4

10 1 w - w Ui U- U- 5 o Cl) Cl) V -'F (3 <2 U) RECURRENCE NTERVAL, N YEARS Figure 5.--Discharge-frequency curve, Cow Creek near Aalea. The recurrence interval, in years, is the average period in which a given event might be equaled or exceeded. t should not be construed to imply any regularity of occurrence. The recurrence interval can be taken as the reciprocal of the probability of occurrence. A 1-year flood has one chance in 1, or a 1 percent chance, of occurring in any year. A 1-year flood has one chance in 1, or a 1 percent chance of occurring in any year. As drawn, the frequency curves are shown as a solid line to the 1-year recurrence interval and are extended as a dashed line to estimate the 5-year flood. t should be remembered that floods of infrequent probability may occur in 2 consecutive years, or even more than once in any one year. Photogrammetric Napping Channel-geometry data required for the step-backwater analysis were furnished by a commercial photogrammetry firm. They produced orthophoto work maps (scale 1 in. = 4 ft) from aerial photographs, with horiontal and vertical map control established to third-order accuracy at primary picture ground-control points. An orthophoto map is an aerial photo mosaic completely corrected for scale and distortion, and is as accurate as a plotted map. The orthophoto map shows all the detail visible on the photograph and includes much detail that would be omitted from a plotted map. Spot elevations, 5-foot ground contours, cross-section locations, and lettering were added. All elevations are given in feet above mean sea level. 5

11 Cross sections were positioned perpendicular to the direction of flow in the channel and, where necessary, were angled to be perpendicular to the flow across the flood plain. Cross-section ground elevations were determined at 1-foot intervals and at topographic breaks across the flood plain. Accuracy of cross-section elevations was to be within ±1 foot for 9 percent of the points where ground surface was visible in the aerial photographs. Contour accuracy was to be within half a contour interval for 9 percent of the area mapped where the ground surface was not obscured by vegetative cover. The distance between cross sections was measured along the stream channel by the photogrammetry contractor. The originals of the orthophoto work maps, not intended for publication, are available for inspection in the office of the Douglas County Planning Department. Collection of Field Data Cross-section locations were spotted on the aerial photographs with thern aid of a stereo viewer prior to the photogrammetric mapping. Water-depth soundings were made in the field at these locations and were later added to the photogrammetric ground elevations to complete each cross section. The location of the cross sections was determined by channel alinement in relation to the flood plain and tributary canyons, and islands in the channel. The cross sections were spaced 1,-1,5 feet (3-45 m) apart, on the average, except on the Umpqua River below Deans Creek where they were spaced more than 2, feet (6 m) apart. Bridges in the project reaches were examined in the field. The dimensions of those bridge openings that were judged to have a significant constricting effect on floodflows were measured in the field. Channel-roughness coefficients required in the hydraulic computations were selected in the field for subreaches through each cross section. Verbal description of bed material and color-slide photographs of the channel were used to aid in office review of the coefficients selected. The aerial photographs were used to assist in selecting roughness coefficients for the flood plain. A water-stage recorder was used to determine the magnitude of the tidal cycle during a period of low flow near the upper end of the project reaches on the Umpqua River, the Smith River, and Scholfield Creek. This measured fluctuation was compared to the fluctuation at Reedsport and used to adjust the water-depth soundings at each cross section. High-water elevations of the December 1964 and January 1974 floods were determined by field observations and interviewing residents and by leveling to nearby bench marks. 6

12 Step-Backwater Analysis The step-backwater method of calculating water-surface profiles uses standard hydraulic equations expressed as functions of channel geometry, roughness, and slope. The profiles are developed by beginning at the most downstream cross section with a known or computed stage-discharge relation and progressively computing profile elevations upstream from cross section to cross section. The theory of step-backwater computation of flow profiles assumes steady-flow conditions. Unsteady flow occurs in tidal-affected reaches of streams. For the purpose of this study, steady-flow conditions are assumed to exist during the moment of maximum tide effect, when water is no longer being stored in the channel but not yet being released from storage. TDAL REACHES Description Umpqua River The study reach on the Umpqua River begins at The Point, near Gardiner, and extends 27 miles (44 km) upstream to the Scottsburg bridge. At very low discharges, the tide elevations at Scottsburg are almost identical to those at Reedsport. The magnitude of the tide effect on 3- to 4-foot (9- to 12-rn) stages at Scottsburg is not known. The channel is generally 1,-2, feet (3-6 in) wide; above Reedsport it is confined in a deep canyon with narrow flood plains. The city of Reedsport is situated on a low flat where Scholfield Creek empties into the Uinpqua River. The river is navigable by shallow-draft vessels to near Scottsburg; a 22-foot (7-rn) channel is maintained to Reedsport. The levees in Reedsport were designed to protect against the 2-year flood. Scholfield Creek The study reach on Scholfield Creek extends from the mouth in Reedsport 7 miles (11 kin) upstream to Wind Creek. Most of the study reach is affected by tide. n the upper 1½ miles (2.5 kin) of the reach, the channel is quite narrow and meanders sharply through low flood plains 6 to 1, feet (18 to 3 m) wide. n the lower 5-6 miles (8-1 krn) of the reach, the channel is 5-1 feet (15-3 in) wide and quite deep. The lowlands are flooded by extreme high tides even though the discharge of Scholfield Creek is quite small. Scholfield Creek heads in the mountains of the Coast Range at an altitude of about 1,2 feet (37 m) above sea level. The upper end of the study reach is at an altitude of 18 feet (6 m) above sea level. The basin is densely forested and sparsely populated. Smith River The study reach on the Smith River extends 21 miles (34 kin) upstream from the mouth to Sulphur Springs. The river winds sharply through the mountains of the Coast Range and has narrow flood plains. The entire reach is affected 7

13 by tide. The river is navigable by shallow-draft vessels to the North Fork. At very low flows, the tidal fluctuation at Sulphur Springs is about twothirds of that at Reedsport and lags 1 to 3 hours behind Reedsport. The magnitude of tidal effect on 2-foot (6-rn) stages at Sulphur Springs is not known. The Smith River heads in the mountains of the Coast Range at an altitude of about 1,2 feet (37 m) above sea level. The basin is densely forested and sparsely populated. Floods in the Tidal Reaches of the Umqua River Basin The highest annual flows of the Umpqua River usually occur from November through March as a result of heavy winter rains augmented by snowmelt; some annual floods have occurred as late as mid-april, primarily caused by snowmelt from the high mountains of the Cascade Range. Flood discharges on the Smith River and Scholfield Creek reflect the direct influence of coastal storm patterns, which may not penetrate far enough inland to cause Umpqua River flooding. Annual peak flows for the Umpqua River were presented in Part 2 (1973) of this series of reports. Annual peak flows for the gaging station on the Smith River, above the project reach at river mile 28.5, are shown in table 1. n the lower estuary area, extreme high tides and strong onshore winds increase flood levels above those caused by high river discharges alone. t is not known how far upstream this increased effect extends. Most of the project reach on Scholfield Creek is subject to flooding caused by extreme high tides and high stages on the Umpqua River. Such flooding is only slightly affected by the discharge of Scholfield Creek. Upstream from the tide-affected reach, the overbank flooding is caused by runoff from heavy rain. Sinlilarly, in the project reach along the Smith River, water levels are directly affected by high tides and high stages of the Umpqua River. However, high tides do not cause overbank flooding on the Smith River unless the SmithS River discharges are also high. Much of the Smith River flood plain has a natural levee along the channel, which impounds sidehill runoff and causes flood-plain inundation even when no overbank flow occurs. Flood discharges used to compute the profiles on the Umpqua River are based on a frequency analysis of the annual-peak data at the gaging station near Elkton. The frequency curve for the Elkton gage was projected downstream to Scottsburg on a drainage-area ratio. The flood-frequency curves for the Smith River and Scholfield Creek were computed from a regional analysis by the Corps of Engineers (1969). Floodfrequency curves used are shown in figures 3 and 4. Flood discharges used to compute the profiles are listed in table 3. 8

14 Flood Profiles in the Tidal Reaches Umpqua River Method. --The stage-frequency curve (fig. 6) used by the Corps of Engineers for the design of the levees in Reedsport was the basis for beginning profile computations on the Umpqua River as well as Scholfield Creek and the Smith River. This curve was developed from a study of the combined effect of high river discharges and high tides. Because of uncertainties of flow distribution and discharge downstream from the Smith River, flood profiles were projected downstream based on observed high-water marks of the December 1964 and January 1974 floods, and channel configuration and predicted high-tide data. Upstream from the Smith River, flood profiles were computed by the step-backwater method. Examination of stage hydrographs for the floods of December 1964 and January 1974 (fig. 7) near Elkton suggests that discharges within 1 foot (.3 m) of peak stage would last long enough to cover one tidal cycle. No attempt was made to compute flood profiles from tide conditions other than those assumed by the Corps of Engineers for the levee design (fig. 6). 5 -j w > w -J w U) w 2 w > - w U- i 1 - > w -J w RECURRENCE NTERVAL, N YEARS Figure 6.--Stage-frequency curve, Umpqua River at Reedsport (from Corps of Engineers). 9

15 w ci w > 3 - w 2 u. 25 w ci DAY, JANUARY 1974 Figure 7.--Stage hydrograph, Umpqua River near Elkton, flood of January Available evidence does not indicate any reversal of flow in the project reach caused by high tides during periods when river discharge is also high. Results. --Upstream from the Smith River, a computed profile for the flood of December 1964 agrees well with known high-water marks of that flood. At cross section 57 a high-water mark on the north bank, on the outside of a sharp bend, is 2½ feet (.8 m) higher than the computed elevation. The computed mean velocity of the water is more than 12 fts (feet per second) or 4 ms (metres per second). At this velocity, 2-3 feet (1 m) of pileup on the outside of a curve is consistent with experience elsewhere and is quite crediible. The profiles are accepted as computed, without adjustment of pileup. 1

16 We have no observed data on the magnitude of tide effect on flood stages at Scottsburg. During the low discharges of late summer, the observed tide elevations at Scottsburg were almost identical to the predicted elevations at Reedsport. At Reedsport, the 1-year flood stage is 12 feet (4 m). At Scottsburg the 1-year flood stage is 4 feet (12 m). A stage-dischargerelation curve at Scottsburg, based on computed elevations of discharges from 1, to 43, cfs (cubic feet per second) or 2,8 to 12, m3s (cubic metres per second), high-water marks of three major floods, and several ossible tide elevations at discharges from 2, to 6, cfs (56 to 17 m's) suggests that the magnitude of tide effect may be l-l½ feet (.3-.5 m) at 1, cfs (2,8 mis) and less than 1 foot (.3 m) at discharges of more than 2, cfs (5,6 m3s). Tidal effects on river flood stages may be expected to increase downstream where the channel is larger and flood elevations are lower. Profile elevations for the selected flows are shown in table 4. The computed profiles, together with maps of the area, are shown in figures The profiles can be related to the adjacent maps for location of the cross sections. The stream boundaries shown on the maps outline the low-water channel. A low-water profile is not shown because of the magnitude of the tidal fluctuations. Plots of the cross sections are shown in figures The profiles of Part 2 (1973) were computed from an estimated stagedischarge relation in Scottsburg based on three high-water marks and a lowwater elevation. The computations of 1974 show the 1- and 5-year profiles to be lower than given in Part 2. The profiles were recomputed from cross sections 1 to 12 of Part 2, and are presented as a continuation of table 4, superseding the elevations shown in Part 2. n the reach from Scottsburg to Reedsport, the flood of December 1964 is equal to the 1-year flood. Upstream from Scottsburg the 1964 flood was lower than the 1-year flood. The profiles for the 1-year and 1964 floods start to diverge at cross section 8 in the narrow canyon above Scottsburg, Scholfield Creek The flood profiles on Scholfield Creek were computed from the concordant flood stages on the Umpqua River at the mouth of Scholfield Creek; that is, the 1-year flood elevation of the Umpqua River was used to compute the 1- year profile on Scholfield Creek. High-water marks of the January 1974 flood show no fall on Scholfield Creek from Oar Creek to the mouth. Step-backwater computations were begun at cross section 22, above Oar Creek. These computations show relatively little fall from cross section 3 to 22. This is consistent with the statement of Albert Maki (oral coinmun., 1973), whose residence is near section 28, that a ttlo_foot tide" (3 m) at Reedsport floods his pastureland to near cross section 3. Correcting the elevation given in the tide tables for the difference between the base station 11

17 and Reedsport and for the difference between mean lower low water and mean sea level, a "1-foot (3 m) tidet' floods land to about 6 feet (2 m) above mean sea level. The constricting effect of the three railroad bridges and the county road bridge between sections 32 and 36 were included in the profile computations. Several additional cross sections, not shown on the photogrammetric map, were used to compute the effect of the bridge constrictions. A few high-water mark elevations for the flood of January 1974 are available, but it was not possible to determine independently the discharge of this flood. The profiles computed appear to be reasonable and consistent with the known extent of flooding. Profile elevations for Scholfield Creek floods are shown in table 5. computed profiles, together with maps of the area showing locations of the cross sections are shown in figures 16 to 18. A low-water profile is not shown because of the tidal fluctuations. Plots of the cross sections are shown in figures 47 to 54. The Smith River The flood profiles on the Smith River were computed from concordant flood stages on the Umpqua River; that is, the 1-year flood elevation of the Umpqua River at the mouth of the Smith River was used to compute the 1-year profile of the Smith River. No attempt was made to compute profiles for other combinations of floodflows of the two streams. A profile for the flood of January 1974 was computed, starting from a high-water mark elevation at cross section 2. The computed profile of the January 1974 flood agrees very well with the prcfile established by high-water marks. The Smith River has a natural levee along the channel throughout most of the project reach. A 1-year flood will overtop this levee at most places. Sidehill runoff from small tributary draws will also flood the land behind the levee, even though the river has not overtopped its primary banks. Water behind the levee returns to the channel through natural tributary drains. The discharge of the January 1974 flood, at the gaging station, was identical to the 1-year flood. At the mouth of the Smith River, the 1-year flood stage of the Umpqua River is 1.1 feet (.3 m) lower than the high-water mark of January 1974 on the Smith River. These two conputed profiles slowly converged; at the North Fork the 1-year flood is only.2 foot or 6 mm (millimetres) lower than the January 1974 flood. This suggests that the influence of the Umpqua River on the Smith River flood stages does not extend significantly beyond the North Fork. Because of the uncertainties of tide influence on various combinations of flow at the mouth, no attempt was made to study this effect in greater detail. Profile elevations for Smith River floods are shown in table 6. The computed profiles, together with maps showing cross-section locations, are shown in figures 19 to 25. A low-water profile is not shown because of the tidal fluctuation. Plots of the cross sections are shown in figures 55 to 7. 12

18 UPPER COW CREEK Description of the Study Reach The study reach on Cow Creek begins 2 miles (3 kin) downstream from Glendale, at the line between Rs. 6 W, and 7 W., and extends 29 miles (47 km) upstream to the mouth of Snow Creek, near Anchor. The Glendale-Aalea Valley is about half a mile wide (1 kin), with a flat flood plain. The channel is quite wide and relatively shallow. The bottom is generally loose, well-graded gravel, with few rock outcrops. The primary banks are 6-1 feet (2-3 m) high. Channel slope averages 16-2 feet per mile (3-4 rnkin). n alluvial valleys such as the Glendale-Aalea Valley, channel-bank erosion and movement of bed material occur during every high-water season. The natural process is for the stream to cut away its bank on the outside of sharp bends and deposit fine material on the inside of bends. Eddies and cross currents affect the movement and deposition of material within the stream channel. Aerial photographs of the valley show evidence of old stream channels that were abandoned in years past, when new channels were cut during a flood. Small meanders and braiding of the low-water channel between the primary banks show the looseness of the bed material. Erosion of the primary banks and the cutting of new channels can be expected to continue as part of the natural geologic process. Upstream from Whitehorse Creek the stream is more deeply entrenched; the valley areas are smaller and are connected by deep canyons. The gradient becomes progressively steeper, as much as 33 feet per mile (6 mkm). Cow Creek heads in the mountains of the Western Cascade Range at an altitude of about 4, feet (1,2 m) above sea level. The uplands are densely forested. Many beaver dams in the project reach impound the low-water flow to a depth of 2-3 feet (1 m). The effect of these darns on flood profiles is considered insignificant. Floods The highest annual flows of Cow Creek usually occur from November through March as a result of heavy winter rains augmented by snowmelt. A few annual floods have occurred as late as mid-april. Annual peak flows for the gaging station Cow Creek near Aalea are shown in table 2. A stage hydrograph for the January 1974 flood is shown in figure 8. The flood-frequency curve for this gaging station is shown in figure 5. A discussion of flood frequency is given on page 3 of this report. Flood Profiles On Cow Creek, the starting stage-discharge relation for the stepbackwater profile computations was computed from a known high-water elevation and slope-conveyance computations. The stage-discharge relation defined by 13

19 1712 -J w > w U, w > o -w w U Note: Recording instrument malfunction \ January 16 (2 am.) to January 17 (4 p.m.) Recession estimated \ -J w DAY. JANUARY 1974 Figure 8.--Stage hydrograph, Cow Creek near Aalea, flood of January 1974 (station 39). current meter at the gaging station near Aalea was used to continue profile computations upstream from that point. The recurrence interval of the flood of January 1974 was greater than 1 years and less than 5 years. Many good high-water marks were found and the elevations were determined by leveling to nearby bench marks. n the Glendale-Aalea Valley downstream from Starveout Creek, there was much bank erosion and many channel changes during that flood. The computed profiles are based on channel conditions existing during the spring and summer of 1973, when the aerial photographs were made and the field survey was done. Near Glendale, the computed profile of the January 1974 flood varied from the high-water marks. Adjustments as much as 1.4 feet (.4 m) were applied from cross sections 5 to 34 to bring the computed profile into agreement with a profile based on the high-water marks. At cross sections 37 and 38, near the Glendale exit from Highway 1-5, high-water marks on the right-bank flood plain were 7 feet (2 m) higher than a high-water 'mark on the left bank of the channel. n this area, floodwater 14

20 breaks overbank at a sharp bend upstream and is carried on the flood plain at a higher elevation than in the channel. The computed profile is representative of the water-surface elevation of the channel. At cross sections 76 and 77, the profile elevations were determined from a computation of critical depth. Step-backwater computations were continued upstream from the critical-depth computations. From cross section 4 to cross section 9, the computed profile was not always in good agreement with the high-water marks, but was allowed to stand as computed because of the uncertainties of channel scour and change during the flood. At cross sections 91-93, 98, and 99, the profiles were adjusted on the basis of high-water marks. At cross sections 113 and 114, there was evidence of scour under the Whitehorse Creek road bridge, and the approach fill to the bridge washed out during the flood. The computed elevation higher than the high-water marks was allowed to stand. At cross section 114, discharges less than the 1-year flood were computed to be supercritical. Step-backwater computations were continued upstream from a computed critical depth at section 114. The profiles from sections 115 to 117 were adjusted to a high-water mark, and the stage-discharge relation of the gaging station 3 feet (1 m) above section 117. The stage-discharge relation at the gaging station is defined by current meter to 7,5 cfs (21 m3s) and by a slope-area measurement of the January 1974 flood, 1,4 cfs (29 m3s). A stage-discharge relation defined by step-backwater computations agrees quite well with the relation defined by current-meter measurements (fig. 9) > w -j w U- 172 'O" 'S > w 17 1, 2, 5, 1, DSCHARGE, N CUBC FEET PER SECOND Figure 9.--Stage-discharge relation, Cow Creek near Aalea (station 39). 15

21 The stage-discharge relation defined by current meter was used to continue step-backwater computations upstream from the gaging station. The profile elevations for cross sections and were adjusted to agree more closely with high-water marks, because the channel appears to be quite stable upstream from Whitehorse Creek. The profiles agreed quite well with high-water marks near sections 133 and 143. At sections 156 and 157, at the Bureau of Land Management bridge, the computed profile is.5 foot (15 mm) higher than the high-water marks. This is considered to be very good agreement because a short approach fill washed Out during the flood. Discharges greater than the 25-year flood submerge the laminated timber girders under the bridge. Profile elevations for the selected flows are shown in table 7. The computed profiles, together with maps of the area, are shown in figures 26 to 35. The profiles can be related to the adjacent maps for location of the cross sections. The stream boundaries shown on the maps outline the low-water channel. A low-water profile is included to give a concept of range in stage. Plots of the cross sections are shown in figures 71 to 88. USE OF THE RESULTS Elevations from the computed profiles (tables 4-7) can be used in conjunction with the plotted cross sections (figs ) to determine the width of the area subject to flooding. This width can be transferred to a suitable topographic map to determine the area inundated by each flood. f the contour interval of the map is sufficiently small, the flood-profile elevations can be plotted directly on the map to determine the inundated area. The plotted cross sections can also be used to determine the stage at which overbank flow occurs and where water might be ponded in low areas of the flood plain. The 5-year flood profiles should be considered as estimates because of the comparatively short period of streamflow record on which the frequency analysis was based. The step-backwater method of computation assumes a level water surface across the width of the channel. Sharp channel curvature or a strong tributary inflow can superelevate the water surface by several feet from bank to bank. n using results of this study, allowance should be made for 2-3 feet (1. m) of superelevation on the outside of a sharp curve. Allowance should also be made for several feet of backwater in areas vulnerable to debris jams. t should also be recognied that overbank flow can become separated from the main channel and be carried at a higher elevation on the flood plain than in the channel. Such conditions are extremely difficult to simulate. Also, low areas of the flood plain can be flooded by local sidehill runoff even though the main stream has not overtopped the banks. The computed profiles are based on channel conditions at the time of the survey. Future channel changes or constriction of the flood plain could also change flood elevations in the affected reach. 16

22 SUMMARY Flood elevations for the selected reaches of the Umpqua River basin are presented in graphic and tabular form. A low-water profile is given for Cow Creek, but is omitted for the other reaches because stages are affected by tide. The profiles presented are in reasonably good agreement with high-water marks. The Cow Creek channel in the Glandale-Aalea Valley is loose alluvial material subject to movement and bank erosion during periods of high water. The profiles computed are for channel conditions of April 1973, when the aerial photographs were taken. REF ERENCES National Ocean Survey, 1972, Tide tables high and low water predictions, 1973, west coast of North and South America including the Hawaiian slands: National Ocean Survey. 1973, Tide tables high aid low water predictions, 1974, west coast of North and South America including the Hawaiian slands: National Ocean Survey. Oster, E. A., 1972, Flood profiles in the Umpqua River basin, Oregon, part 1: U.S. Geol. Survey open-file rept. 1973, Flood profiles in the Umpqua River basin, Oregon, part 2: U.S. Geol. Survey open-file rept. U.S. Army Corps of Engineers, 1966, Detailed project report on levee improvement project, Umpqua River at Reedsport, Oregon: U.S. Army Corps of Engineers rept. 1969, Procedure for determination of maximum annual flood peak and volume frequencies for Portland District, Oregon: U.S. Army Corps of Engineers rept. 17

23 Table 1. --Annual peaks for Smith River near Gardiner, Oreg. (station 3231) Water year Date Gage height (in feet) Discharge (in cfs) 1961 Feb. 1, "26, 1966 Jan. 3, , Jan. 28, , Feb. 23, , Dec. 4, ,7 197 Jan. 26, , Jan. 16, , Jan. 21, , Dec. 22, , Jan. 16, , 1 Revised August

24 Table.--Anrival peaks for Cow Creek near Aalea, Oreg. (station 39) Water year Date Elevation (in feet above msl) Discharge (in cfs) 1928 Mar. 27, , Apr. 14, , Dec. 14, , , Apr. 1, , Jan. 2, , , Jan. 23, , Jan. 7, , Jan. 13, ,72.5 2, Apr. 13, , , Feb. 6, , , Mar. 12, ,71.2 1, Feb. 28, 194 1, , Jan. 27, ,71.2 1, Dec. 18, , , Jan. 21, , , Nov. 4, , Feb. 8, ,7.52 1, Dec. 28, , , Mar. 1, ,7.2 1, Jan. 6, , , Feb. 22, , , Jan. 23, 195 1,7.44 1, Oct. 29, 195 1, , Feb. 1, , , Jan. 18, , , Jan. 27, , , Dec. 31, , Dec. 21, ,77.8 5, Feb. 26, , , Jan. 29, , , Jan. 12, , ,1 196 Feb. 8, 196 1, , Feb. 1, ,73.3 3, Nov. 23, , , Dec. 2, , ,87 19

25 Table 2. --Annual peaks for Cow Creek near Aalea, Oreg. (station 39)--Continued Water year Date Elevation (in feet above msl) Discharge (in cfs) 1964 Jan. 2, , , Dec. 22, , , Jan. 5, , , Jan. 28, , , Feb. 23, ,71.5 2, 1969 Jan. 12, , ,4 197 Jan. 26, 197 1, , Jan. 17, , , Mar. 2, , , Dec. 22, , Jan. 15, , ,4 2

26 Table 3.--Discharges used to develop the flood profiles Discharge, in cubic feet per second 5-year flood 1-year flood 5-year 25-year 1-year 2-year f1 f1re1 f1cd f1rrd December 1964 F1r1 January 1974 f1rr-1 1-year flood (iiii-pd'- Umpqua River above Smith River 43, 329, 287, o 246, 196, 16, 329, 256, 262, Scholfield Creek above Oar Creek 2,9 2,3 2, o 1,8 1,6 95 Smith River above North Fork 5, 38, 33, 29, 24, 14, 24, Smith River below North Fork 65, 5, 44, o 39, 33, 2, 33, Cow Creek gaging station 39 11, 9,16 8,26 7,28 5,82 2,6 1,4 1 Adjusted for storage in proposed Days Creek Lake.

27 Table 4.-- Profile elevations for Uopqu River below Scottbur Distance up- Elevation, in teet above mean sea level stream from 1-year 1-year Cross The Point flood 5-year Diceniber year 25-year 1-year 2-year section (feet) (adjusted)- flood flood2i flood flood flood flood Tha1weg. 8, , , , Sc,lfield Cr. 18,4 5 19, Hghway 11 19,81 Railroad 21, , Smith River , , , , l 32, , , , , , , , , Dean Creek 48, , , , L , , , , , , , , , , , , , , , , , , , , , , , , \ , t , , , , Mill Creek 87, , , , , , , , , , , , , Footnotes at end of table. 22

28 Table 4 --Profile elevations for Umpqua River below Scottsbur--Centinued Distance up- Elevation, in feet above mean sea level stream from 1-year 1-year Cross The Point flood 5-year December year 25-year 1-year 2-year Section (feet) (adjusted)i' flood fld.a flood flood flood flood Thalweg , , , , Highway 38 bridge 69 14,115 14, Revision of Sectiqns Part 2, 1973 Distance up- Elevation in feet above mean sea level stream from 1-year Cross Scortsburg December 1964 flood 5-year 1-year 5year 25-year 1-year 2-year section bridge (ft) flood (adjusted)1 flood flood flood flood flood flood , , , , , , , , , , , Gaging station , f Adjusted for storage in proposed Days Creek Lake. 2 December 1964 flood identical to 1-year flood. 3 Thaiweg, low point in channel.

29 Table 5. --Profile elevations for Scholfield Creek stance up- Di Elevation, in feet above mean sea level stream from Cross mouth 5-year LOG-year 5-year 25-year 1-year 2-year Section (feet) flood flood flood flood flood flood Thalveg- 1 2, , , , Highway 11 5, , , , , , , , Railroad bridge 12, , , , , , , , , , , Oar Creek 23, , , , Railroad bridge 28, , , Private road bridge 3, , , , , , , A 37, Railroad bridge 37, , , A 38, Railroad bridge 38,4 234C 38, D 39, Railroad bridge 39,45 234F 39, , A 4, County bridge 4, , , Wind Creek 4,48 1 Thalweg, low point in channel. 2 Section not shown on photogrammetric mop. 24

30 Table 6.. -ProfiLe elevat ices for the Smith River Cross section Distance upstream from mouth (feet) January 1974 flood 5-year flood Elevation 1-year flood in feet above mean sea level 5-year 25-year 1-year flood flood flood 2-year flood Thalwegi 6, , , , Fraut Creek 12, , , County bridge 16,715 Hudson Slough 17, , , , , Otter Slough 21, , , , , , , , Joyce Creek 31, , , , , , , , Noel Creek 38, , , , , , a'3 45, , , , Eslick Creek 48, , , , , , , , , , , , , , , , , , , , , , , , Footnotes at end of table. 25

31 Table 6.--Protilo elevations for the Smith River --Continued Distance up- Elevation in feet above mean sea level stream from January Cross mouth year 1-year 5-year 25-year 1-year 2-year section (feet) flood flood flood flood flood flood flood Thalwegl' Log dump 73, , , , , , , , North Fork Smith R, 83, ,445 18, , , , , , , , , , , , , , , , , , , , , Wassen Creek 15, , , , , , ,7-1.4 Sulphur Springs 11, , , , , ,4 1 Thaiweg, low point in channel. 2 Noel boat ramp. 26

32 Table 7.- -Profile elevations for Cow Creek 8bove G1end1e Cross section Distance upstream frqm sec. il' (feet) January 1974 flood 5-year flood Elevation, in feet above mean sea level 1-year 5-year 25-year 1-year flood flood flood flood 2-year flood Low water Thalwega 1 1, , , , , , , ,346_a 1, ,6 1, ,367. 1,366. 1, , ,363. 1, ,35.4 1, ,955 1, , , , , , ,36. 1, , ,35 1, , , , ,371. 1, , , , ,88 1,376. 1, , , ,374. 1, , , , ,84 1, , , , , , , ,36.4 1, ,465 1, ,38. 1, , , ,376. 1,37.3 1,361. 1, ,33 1,38.2 1,38.6 1, , ,378. 1, ,37.8 1, , ,29 1,381. 1, ,38.1 1, , , , ,363. 1,36. Railroad bridge 7,37 1 7,52 1, , ,381. 1,38. 1, , , , , ,35 1, , , ,38.7 1, , , , , ,76 1, , , , ,38.3 1, , , , ,75 1, , , , , ,38.4 1, , , ,495 1, , , , , , , , , ,285 1,386. 1, ,385. 1, , , , , , ,17 1, , , , , ,384,4 1, , , ,46 1, , , , , , , , , ,525 1,39.4 1,39.6 1, , , ,388. 1, ,379. 1, ,785 1, , , , ,391. 1,39. 1,387. 1,38.6 1, ,72 1, , , , , ,392.1, , ,381.8 Railroad bridge 17, ,99 1, , , , , , ,39.8 1, ,382.5 County bridge 18, Windy Creek 18, ,135 1,399. 1, , , , ,397. 1,394. 1, ,385.4 Glendale bridge 19, ,37 1,4.6 1,4.9 1,4. 1,399,6 1, , , , , ,915 1,41.2 1,41.5 1,4.8 1,4.4 1,4. 1, , , , ,195 1,44.4 1,44.8 1,44. 1,43.4 1,43. 1,42. 1,399. 1, , ,3 1,47. 1,47.3 1,46.5 1,46.2 1,45.7 1,45. 1,42. 1, , ,635 1,49.5 1,49.8 1,49.1 1,48.6 1,48.2 1,47.5 1,44.3 1, , ,875 1,412, 1,412,3 1, , ,41.6 1,49.7 1,46.8 1, , ,73 1, ,414. 1, ,413. 1, , ,48.2 1,41.5 1, ,655 1,417,2 1,417,4 1, , , , ,41.3 1,44. 1, ,675 1, ,419. 1, ,418. 1, , , ,48.8 1, ,34 1,42.1 1,42.4 1, , , , , ,49.8 1, ,355 1,422. 1, , ,421. l,4z.4 1, , , , ,275 1, , ,424. 1, , , , ,413. 1, ,34 1, , , , ,45.7 1, ,421. 1, , ,88 1, , ,429. 1, ,428. 1, ,424,6 1,42.2 1, ,6 1, , , , , ,43.4 1, , ,42.6 Glendale Junction bridge 34, ,445 1, , , , , , , , , ,345 1, , , ,437. 1, , , , , ,9 1, , , ,441,4 1,44.7 1, , , , ,96 1,444. 1, , , , , , , , ,81 1, , , , , , , , , ,47 1, ,446. 1,445,4 1,445. 1, ,444. 1, , , ,54 1, , , ,448. 1, ,446:8 1, ,44.6 1, ,385 1, , , , ,45.7 1, ,447. 1, , ,235 1, , , ,453. 1, , ,449. 1,444. 1, ,935 1, , , , , ,453. 1,45.2 1, , ,635 1,457,1 1, , , , , , , , ,29 1,46.2 1,46.4 1, , , , , , , ,715 1, , , ,462. 1, , , , , ,53 1, , , , , , , , , ,3 1,469. 1, , , , ,467. 1, ,461. 1, , 1,47. 1,47.3 1, , , ,468. 1, , , ,1 1,474. 1, , , , ,47L.9 1, ,467. 1,464.9 Woodford Creek 48, ,95 1, , , ,476. 1, , , ,47.4 1, ,12 1,48.4 1,48.6 1,48.2 1,48.1 1, , , , ,469.8 Footnotes at end of table. 21

33 Footnotes at end of table. Table 7.--Profile elevatloos for Co,i Creek above Glendale- -Continued Distance upstream from January ELevation. in feet above nean sea level Cross sec year 1-year 5-year 25-year 1-year 2-year Low section (feet) flood flood flood flood flood flood flood water maiwega 57 51,6 1,485. 1, , , , , ,48.2 1, ,472.2 Old bridge site 52, ,18 1, ,487. 1, , ,486. 1, , , , ,95 1,49.6 1,491. 1,49.2 1, , , , , , ,525 1,493. 1, , , , , , , , ,735 1, , , , , , , , , ,745 1,5. 1,5.2 1, , ,499. 1, , , , ,75 1,54.8 1,55. 1,54.5 1,54. 1,53.7 1,53. 1,51.2 1,497. 1, ,49 1,55.4 1,55.6 1,55.1 1,54.7 1,54.4 1,53.7 1,52. 1, , ,785 1,51.7 1,51.9 1,51.4 1,51.1 1,59.8 1,59.2 1,57.2 1,53.4 1, ,61 1,514. 1, , , ,513. 1, ,51. 1,55.5 1, ,34 1, , , , , , , ,57. 1, ,65 1, , , , , ,52.3 1, ,51.4 1, ,78 1, , , , , , ,52.2 1, , ,725 1, , , , , , ,523. 1,518. 1, ,71 1, , , , ,53.4 1, ,526. 1, , ,57 1,536. 1, , ,535. 1, ,533. 1, , , ,75 1,537. 1, , , , , , ,529. 1, ,88 1, , ,544. 1, ,543. 1,542. 1, , , , 1, , ,547. 1, , ,545. 1, ,539. 1,535. Quines Creek road bridge 7,5 76 7,285 1, , , , ,547. 1, , ,54.8 1, ,225 1, , ,55.7 1,55.2 1, ,549. 1,547. 1,545. 1,542.6 Quines Creek 71, ,5 -- 1, , , , , , , , ,542.4 Rigaay 1-5 bridge 72,37 72,18 Highway -S bridge 79 72,895 1,56.2 1,56.6 1, , , , , , , ,86 1, , , , , ,56.7 1,557. 1,552. 1, ,86 1, , , , , , , , , ,79 1, , , , , , , , , ,54 1,573. 1, , , , ,57.2 1, , , ,32 1, , , , , , , ,564. 1, ,5 1, , , , , , , , , ,685 1, , , , , , , , , ,61 1, , , ,58.7 1,58.3 1, , , , ,4 1, , , , , , ,579. 1, , ,64 1, , , , , , ,585. 1,58.4 1, ,485 1, , , , , , , , , ,54 1,62.6 1,62.9 1,62.2 1,61.7 1,61.4 1,6.6 1, ,593. 1, ,555 1,64.9 1,65.1 1,64.5 1,64.1 1,63.7 1,63.2 1,6.8 1, ,593.2 Starveout Creek 85, ,53 1,67. 1,67.2 1,66.6 1,66.2 1,65.9 1,65.3 1,62.7 1, ,594.6 County bridge 85, ,5 1,69.4 1,69.6 1,69. 1,68.6 1,68.2 1,67.4 1,64.6 1, , ,665 1, , , , , ,61.7 1,68.6 1,62.8 1, ,865 1,62.4 1,62.8 1, , , , , ,65.5 1, ,84 1, , , , ,62.5 1, , ,66.8 1, ,8 1, , ,627. 1, , ,625. 1, , , ,52 1, , ,633. 1, , , , , , ,255 1, ,639. 1, , , , , , , ,35 1, , , , , , , , , ,12 1,647.7 L, , ,647. 1, , , , , ,83 1, , , , , , , , , ,85 1, , , , , , , , , ,125 1, ,658. 1, ,657. 1, , , , , ,58 1, ,66. 1, , , , , , , ,875 1, , , , , , ,66.2 1, , ,645 1, , , , , , , , , ,l8S 1, , ,678. 1, , , , ,67.6 1, ,725 1, , , , ,68.7 1,68. 1, , , ,815 1, , , , , , , ,679. 1,

34 1 Cross section 1 at line between Rs. 6 W. and 7 W. 2 Thalweg, low point in channel. Table 7. --Profile elevations for Cow Creek above Glendale--Continued Distance upstream frgm January Elevation in feet above mean sea level il 1Q7L coo-year 1-year 5-year 25-year 1-year 2-year Low section (feet) flood flood flood flood flood flood flood water Thalweg_ ,84 1, , ,696. 1, ,695. 1, , ,686. 1,684. Whitehorse Creek 13, ,25 County road bridge 14,22 1,7.4 1,7.6 1, , , , , ,692. 1, ,4 1,71.6 1,72.2 1,7.5 1, ,699. 1,698. 1, , , ,28 1,72.4 1,72.8 1,71.7 1,71.3 1,71. 1,7.2 1, , , ,3 l,73.s 1,74.1 1,73.1 1,72.7 1,72.2 1,71.3 1, , , ,425 1,78.8 1,79.1 1,78. 1,77.4 1,76:7 1,75.5 1,71.9 1, ,691.6 Caging station 39 17,735 1,71.7 1,711. 1,79.8 1,79.1 1,78.4 1,77.1 1,72.8 1, , ,35 1, , , , ,71.5 1,79. 1,74.6 1, , ,275 1, , , , , , ,77.7 1,71.8 1, ,28 1, , , , , , ,712. 1,77. 1, ,215 1, , ,72.7 1,72. 3, , , ,79.7 1, ,845 1, , ,723. 1, , ,72.8 1, ,711. 1, ,72 1, , , , ,725. 1, ,72.8 1, , ,4 1, , ,733. 1, , ,73.8 1, ,724. 1, ,175 1, , , ,737. 1, , , , , ,945 1, ,742. 1,74.9 1,74.2 1, , , ,73.8 1, ,75 1, , , , , , , , , ,8 1, , , , , ,751. 1, , , ,32 1, ,759. 1, , , ,756. 1, , , ,875 1,76. 1,76.3 1, , , , , ,749. 1, ,775 1, , , , ,761. 1,76.1 1, ,753. 1, ,85 1, , ,765. 1, ,764. 1, ,76.6 1, , ,25 1, ,769. 1, , , , , , , ,53 1, , , , , , , , , ,465 1,781. 1, ,78.2 1, ,779. 1, , , , ,665 1, , , , , ,78.8 1, ,772. 1, ,635 1,787. 1, , , , , ,78.8 1, , ,985 1, , , , ,79.7 1, , ,78.4 1, ,935 1, , , , , ,793.6 l, , , ,75 1,81.3 1,81.4 1,8.9 1,8.4 1, , , ,788. 1, ,15 1,87. 1,87.4 1,86.3 1,85.6 1,84.9 1,83.7 1,8. 1, , ,96 1, , , , , ,81.3 1,87. 1,82.2 1, ,28 1, , , ,821. 1,82.4 1, ,817. 1,814. 1, ,17 1,831. 1, ,83.4 1, , , , , , ,87 1, ,84.3 1,839. 1, , , , , , ,825 1,849. 1, , , , , , ,838. 1, ,865 1, , , , , ,85.7 1, , , ,35 1, , ,858. 1, , , , , , ,35 1, , ,865. 1, , , , , ,852.4 Negro creek 14, ,7 1,87.5 1,87.8 1, , , , , ,86.4 1, ,935 1, ,877. 1,876. 1, , , , ,866. 1, ,64 1, , ,879. 1, , , , , , ,715 1,883. 1, , , , ,88.1 1,877. 1, , ,58 1, , , , , , ,88.7 1, , ,69 1,89.2 1,89.4 1, ,889. 1, , , ,88.8 1, ,75 1, , , ,894. 1, , , , , bridge 147, ,2 1, , , , , , , , , ,6 1,899. 1, , , , , , , , ,65 1,92.7 1,93. l.92.l 1,91.6 1,91. 1,9. 1, , , ,18 1,96.6 1,96.8 l.96. 1,95.5 1,94.8 1,93.7 1, , , ,3 1,91.2 1,91.5 1,99.6 1,99.2 1,98.5 1,97.4 1,93.8 1,9.2 1, ,55 1, , , , , , ,98. 1,93.5 1, ,635 1, , , , , , , ,97.5 1, ,46 1, , , , ,92.6 1, , , , ,31 1, , , , ,925. 1,924. 1,92.6 1, , ,945 1,929. 1, , ,928. 1, , , , ,917.4 Snow Creek 156,2

35 EXPLANATOd H,h wot..r -yoo flood OO-yoor flood ()croo secoro yeor flood lo--ynor flood -- o End of profle sfown 2 SCALE, N FEET K t2, 16, D STANCE UPSTREAM FROM CROSS SECTON ONE, N FEET FGURE 1.-- P rofiles of Umpqua River.

36 Bolon 5lond & LEVEL SEA MEAN o) EXPLANA11ON OG-yeor flood -year flood 2ear flood -year flood a High rioter CrO,eChOOO O End of profile hoen (DO 2 SCALE, N FEET ABOVE 4 FEET 3 N ELEVATON, 2 18, 2, O 28O 3 34p FROM CROSS S roffles of Umpquo

37 EXPLA 5-year flood -year flood 25-year flood -year flood --n End of protde nhown 2 SCALE, N FEET 4, 42, 44, 46, DSTANCE UPSTREAM FROM CROSS SECTON ONE, N FEET Fl GURE 2-Profites of Umpquo River

38 6 5 5-yoor flood OO-yeoo flood 25-yeo, f'ood O-yoor flood EXPLNdATON Hrgfl woter Ct otion End of profile shown 2 SCALE, 4 FEET , 54OO 54 DSTANCE 5O 6, 62, 64, 66, 68 UPSTREAM FROM CROSS SE CTON ONE, N FEET F SURE Profi'es of Umpqua River.

39 7 LUd8 Cre OO-oo flood OO-yeo flood 25-yoor 1ood -year flood EXPLANA11O!d HQh eofer Cr5 eachono --a End of profile Shown SCALE, N FELT 2 L 68, 7, 72 74, , 82, 84, DSTANCE UPST REAM FROM CROSS SECTON ONE, N FEET 14--Profiles of Umpquo River,

40 8 5 w w 6 -yaor f:oad - -yea, floed yeac foc -year tood EXPLM48TJ Hgr note, sections o---o End at profe nhoen 2 SCALE, N FEET w 5 2 > 2, F- 4 uj uj LL , Q > uj 3 2 l 86, , , 98, 4+, + 2, D STANCE UPSTREAM FROM CROSS SECTON ONE, N FEET F GURE 5 - Profiles of Umpqua River

41 UiSUA RVEA a ç'yo REEDSPORT a (3 5 't (flaa 4 (i) () , Hgh Walor foo-yor flood - 1-year flood End of peofde Otroern :: SCALE, N FEET p l4 6 D STANCE UPSTREAM FROM MOUTH, N FEET F GURE &-Profiles of Scholfied Creek.

42 J uj > w 6 LU 5-year flood u) -year flood 5 2S-,eor flood 1-year flood LU uj 4 > EXPLA ta1on Hq wo?o o--- Er,d of prfie oho,or, co 2 SCAlE, N FEET LU LU Li > LiJ uj H 4+ 8p 2, 22, 24, 26, 28, DSTANCE UPSTREAM FROM MOUTH, N FEET F GURE 17-- Profes of Scholfied Creek. 3, 32, 34,

43 EXPLANATON year flood 1-year flood 25-year flood O-yeor flood 4gh woter Cross ctron O---O Eed of profile shown fooo2oo SCALP, N FEET Combrned with 2 year flood 34, 36 38, 4, 42, 44, 46, 48, 5 DSTANCE UPSTREAM FROM MOUTh, N FEET F GURE & - Profiles of Scholfield Creek.

44 Blocks s OO-yeor flood OO-yooi- flood yoor flood l-yoor flood EXPLANAT1O Hs soter Cross scolloos - o End of protilo thown 2 SCALE, N FEET 3 2 to 6. 8,, D STANCE UPSTREAM FROM MOUTH, N FEET F GURE 19-- P rofiles of Smifh River.

45 Src,nar Creek 7 6 OO-yoor flood ycor flood yenr flood l-oor flood EXPLANATON Hgh ootcr Croon aoctint -. - End of prolo thoon 2.1 SCALE, N FEET , 2, 22, 24, 26, 28, 3, 32, D STANCE UPSTREAM FROM MOUTh, N FEET FGURE 2"Profiles of Smith River.

46 ('J 1JJ 7 LEVEL SEA MEAN ABOVE FEET N ELEVATON, OO-yr 5-ycor cd fooj Bocd lo-ycor flood EXPL1,A1OJ * High,Jotcr Croov scflo yeo - o End of profilo 2 SCALE, N FEE , 38, 42, 46, 8 48, 5, REAM FROM,, ;i C G) Profiles of

47 7 EXPLANA11ON 6 5-yoor flood -year flood 25-year flood lo-yeor flood 5 A Hgh wn )Crose sectjon; --n End of profire Shown C SO 2 SCALE, N FEET , 54, 56, 58, 6 62, 64, 66 68, DSTANCE F UPSTREAM FROM MOUTH, N FEET Rwer. GuRE2a--profes of Smith

48 EXPLANA1N Mu,-py Creek 5-ynw flood OO-yeo flood 25-yoor flood -yeor flood Hgh nwtor Cr noct End of profile shown 2 SCALE, N FET , 7, 72, 74, 76, 78, 8, 82, - 84, D STANCE UPSTREAM FROM MOUTh, N FEET F GURE 23--P rofiles of Smith River

49 ifr (o 11 ' EXPLANAT!4 -yor flood i-yoor flood yoor flood i-yoor flood o High vio?or CcOn con End of profile nhown SCALE, r1 FEEl + 3 _T 2 86, 88, 9, 92, 94, 96, 98, ', 12, D STANCE UPSTREAM FROM MOUTH, N FEET F GURE 24- -Profiles of Smith River.

50 Sulphur $J wo:: \ U () EXPL4A11ON H$gh water 5-year tioad year flood Croae Oechna O o End Cf profle shown -year flood SCALE, N FEET , 4, 6, 8, to, 112, t4, D STANCE UPSTREAM FROM MOUTH, N FEET F GURE 25--Profiles of Smith River.

51 EXPLANATON OOieo flood OO-eo, flood eor flood lo-ieor flood Lo.o!er Tholoç 9 High RotOr 5,,5 Cross s.ctl1 - - End of profile Shown SCALE, N FEET D STANCE UPSTREAM FROM CROSS SECT ON ONE, N FEET F GURE 26-- Profiles of Co Creek.

52 (21' o.:l. 4 ':J;.k' :iu _ EXPLANATON 5-year flood 1-year flood lood la-year flood Hgh wale, mark Gross neclions -- End of profile shown SCA,.ENFT 138 2, 24 26, 22OO 28OO 3Q DSTANCE UPSTREAM FROM CROSS SECT ON ONE, N FEET 32, 34p GURE 27--Profiles of Cow

53 48 G1EMLE fl4ctn - 46 d o-o G) T io old1:! EXPLANATiON ' Thh.g SCALE, N FEET , 36 38p 4, 42, 44, 46P 48, DSTANCE UPSTREAM FROM CROSS SECT ON ONE, N FEET FGURE 28 Proffles of Cow Creek.

54 54 -J LU > uj -J w U) LU 52 LU LU LU 5 - > 48 Ui OOier Esod ioo-en' f'ood yeo, flood lo-e,, flood Los water Thateeg EXPLANATON rgs water no,k Cross sections End of p.of,e Shown r SCALE. fn FEET 2Op 52, 54 56, 58, 6, 62, 64, DSTANCE UPSTREAM FROM CROSS SECTON ONE, N FEET 66 68, F GURE 29-- Profiles of Cow Creek.

55 -J LU > U -J LU LU L 1JWP uj F- 56 Lii Lii U- + > 54 LU i EXPLANATON 2OO - SCALE, N FEET , 7, 72, 74, 76, 78, 8, 82, 84, DSTANCE UPSTREAM FROM CROSS SECT ON ONE, N FEET F GURE 3- - Prof iies of Co Creek.

56 R'5ge o L 'vi -J w -J LJ () i LU LU > 64 + ffi., LU LU U- > LU -J LU OOlO,ES::ANAToNA Hh Oe n,a, loqiso, flood 2-.o,d Cooi ---Eod of po(le.own SCALENftET , 93, 95 97, 99, 11, D STANCE UPST REAM FROM CROSS SECT ON ONE, N FEET 85, 87 F GURE Profiles of Ccm Creek.

57 -J uj -J if uj () uj w 72 > - uj uj U- 7 > UJ -J UJ 68 '7 f toad!.!.!, + 1ExPNATN -.. -yea, y.o, flood Qua, flood -. End ad p,ofil. oboan - - LCo, *1, 9 a - SCALE, N f5 7 5, 7 9 3, 15, 7, 119, DSTANCE UPSTREAM FROM CROSS SECTON ONE, N FEET 13 F GURE 32--P rofiles of Ccw Creek.

58 D 84 -J uj > uj -J LU LU Ui > 4-78 LU UJ U- > 76 LU 74 9, VA!!<'<A 4 OO-,o flood 1, flood yoo, flodd EXPLANATON Nh OlO k () c,oi, ocfono End of p,of,fs hon 2 CALEN FEE 121, 23, 125, 27, 129, 13, 33, 35, DSTANCE UPSTREAM FROM CROSS SECTON ONE, N FEET F GURE 33--Profiles of C Creek.

59 - uj tjj Li > uj -J ft od :: - - E d ad tool ha. 9 2 Sugrar Creek EXPLANATiON AU Lao Thot.eg SC*. FEET J uj J 9 uj (1) uj w 88 > 84 39, 141, 143, 145, 47, 149, 151, 53 DSTANCE UPSTREAM FROM CROSS SECTON ONE, N FEET 37, F GURE 34--Profiles of Cow Creek.

60 -J w -J J Cl) w j 94 > ':1: - JJ w U- 2 - > Low 5OO-ynr Eood OO-yeor flood tlod -year flood wale, Tholmag EXPLANATON 9 9 on monk Cross tclool End of moflie Ofloan SCALE, N FEET 2ODO Ui 9 53, 55, 57 59, D STANCE UPSTREAM FROM CROSS SECT ON ONE, N FEET F GURE 35 - Profiles of Cc Creek.

61 18ff balls 2 Right bari CROSS SECTON * JLU J -1 LU LU -2-3 a LU > a CROSS SECTON LU U- 1 LU -1 EXPLANATON year flood - 11-year flood 125-year flood 1-year flood HORZONTAL SCALE, FEET -5 -G CROSS SECTON 3 \

62 Left bank 3 r- Rht bonk U N U U CROSS SECTON n _ 1 LU _ 1) LU (1) CROSS SECTON CROSS SECTON EXPLANATON 5-year flood._r1yer flood 25year flood 1-year flood 8 6 HORZONTAL SCALE, F FEET FGURE 37-- Umpquo River cross sections 57

63 Left br 3 Right bank CROSS SECTON 2 7 ft 36 *8 3 2 J 1 r EXPLANAON 5O-year flood 1-year flood 25-year flood 1-year flood 8 6 HORZONTAL SCALE, N FEET '-! CROSS :: -1 SECTON J L CROSS SECTON * 12. CROSS SECTON FGURE 38--Urnpqua River cross sectkns 58

64 2 Left bank fint Left Right book o CROSS SECTON CROSS SECTON *2 36 bross SECTON EXPLANATON 5-year flood -year flood 25-year flood 1-year flood HORZONTAL SCALE, N FEET * 36 CROSS SECTON l o * CROSS SECTON 15 2 FGURE 39.--Umpqua River cress-sections

65 Loft book 3 Rghl book 3 Left book R49hf book OO CROSS SECTON 1? CROSS SECTON 3 3 -J tj (_1) a tj 1-1 w - ii CROSS SECTON C CROSS SECTON CROSS SECTON 2 2' 4 12 CROSS SECTON EXPLANATON 5-year flood 1-year flood year flood 1-year flood 8 tgoo HORZONTAL SCALE, N FEET FGURE 4-- Umpqua River cross sections Go

66 Loft bank RQht bank Loft bank WQO# bank 3 3u 2 L t CROSS SECTON 22 CROSS SECTON U 1 1 C CROSS SECTON 24 CROSS SECTON ' 2 CROSS SECTON 2 *2 1 CROSS SECTON EXPLANATON 5-year flood - 1-year flood year flood lyear flood y HORZONTAL SCALE, N FEET 6 CROSS SECTON *2 2 CROSS SECTON 29 FGURE 41--Umpqua River cross sectbns 61

67 3 Left bank Rh! bank Sb 12 2 CROSS SECTON 3-3 CROSS SECTON 31 CROSS SECTON w > w w U ru UW kit UN V ago W CROSS SECTON 35 F CROSS SECTON CROSS SECTON N, toga LU : ago 7 2 CROSS SECTON \ CROSS SECTON 37 EXPLANATON 5-year flood OOyear flood 25-year flood -year flood CROSS SECTON 38 8 OO HORZONTAL SCALE, N FEET FGURE 12--Umpquu River cross sections 62

68 4 bank RM bank Left boab Rhf bob Left bank Rgh k U -2-3 CROSS SECTON C 3 12 CROSS SECTON $ CROSS SECTON uj Ui 1 Ui Ui - H -2 F N 1 ci -2 * 2 4 * $2 CROSS SECTON 42 CROSS SECTON 43 CROSS SECTON EXPLANA11ON 5-year flood OOyear flood 25-year flood -year flood HORZONTAL SCALE, N FEET CROSS SECTON 45 CROSS SECTON 46 FGURE 43--Umpqua River cross SeCliors 63

69 4 Left bank Rh? bank Left bank 4 Right bank 4 Left bank gb? bank NJ 3 CROSS 4 12 SECTON 4? 3 CROSS SECTON toon 4 48 CROSS SECTON 49 4 '4 4 _J lj w lid w > C - LU to-on C on 2 CROSS SECTON 5 CROSS SECTON 51 CROSS SECTON \} > LU J U_ EXPLANATON SOOyear flood OOyear flood year flood -year flood 2 U HORZONTAL SCALE, N FEET 3 CROSS SECTON 53 on, 3 N CROSS SECTON 5L FGURE 44.--Umpqua River cross sections 64

70 Left bank Roh bor Left bank Rich? bank Left bunk Right bank colt CROSS SECTON a -3 coo todd -3 * loon CROSS SECTON 56 CROSS SECTON U QO 1 2 U CROSS SECTON 58 CROSS SECTON J *22 CROSS SECTON 6 EXPLANA11ON 41 4 SOOyear flood year flood 25-year flood year flood BOO 16 HORZONTAL SCALE. N FEET kod CROSS SECTON 62 2 CROSS SECTON 61 FGURE 45--Umpqua River cross sections 65

71 6 Left bank Right bonk 6 Let bank Right bank 6 Left baik Right bank ii o 12 CROSS SECTON 64 CROSS SECTON 65 CROSS SECTON uj _J :: : LU : CROSS SECTON \ -1 V D 12 CROSS SECTON 67 CROSS SECTON T 1 \J J 22 CROSS SECTON EXPLANATON SOO-year flood -year flood year flood 1-year flood HORZONTAL SCALE, N FEET FGURE 4.-- Umpquo River cross sections 66

72 Left bank Right bank 3 Left kook 5ght bank 2 1 F CROSS SECTON CROSS SECTON _j CROSS SECTON 3 CROSS SECTON - lj d EXPLANATON 5year flood 1-year flood 25-year flood year flood 4 8 HORZONTAL SCALE, N FEET 3 CROSS SECTON N -2 CROSS SECTON SO FGURE4?--Scholfield Creek cross sections 67

73 3 Left bonk Right bork C L 3 CROSS SECTON uj Lii -1 2f CROSS SECTON 3\ \\ CROSS SECTON OU EXPLANATON 5year flood Ooyearflood 25-year flood -year flood CROSS SECTON HORZONTAL SCALE, N FEET FGURE 48Scholfield Greek cross sections 68

74 Lef book 3 9ht book CROSS SECTON J ? 9 CROSS SECTON () tj 3 2 1! 1 CROSS SECTON UJ 2 1 \ EXPLANATON 5-year flood 1-year flood year flood year flood 1OO CROSS SECTON 3C 5 ' HORZONTAL SCALE, N FEET 2 1 U CROSS SECTON FGURE49-Schofield Creek cross sections 69

75 Left book 3 Right bo4sk 3 Left book gh$ book NJ U J tj 2 CROSS SECTON CROSS SECTON 1? uj C,, ci: uj l, CROSS SECTON TOO $ Jor th ass ctc 2 EXPLANATON 5-year flood -year flood -year flood 1-yeas flood 1 4 HORZONTAL SCALE, N FOT 2 CROSS SECTON 1t 3 5 F GURE 5Scholfie d Creek cross sect ons

76 4 Left bank FEQh bn ± , J 3 5 CROSS SECTON too (1) 3 uj 2 V - EXPLANA11ON 5-year flood -year flood 25-year flood -year flood 4 8 HORZONTAL SCALE, N FEET too 3 5 CROSS SECTON too U CROSS SECTON 22 too too 3 CROSS SECTON 23 F GURE 51--Scho fed Creek cross sections

77 4 LoU book Right bank C CROSS SECTON 2q Ui Ui - Ui CROSS SECTON \ - 7 J EXPLANA11ON 5CC-year flood 1-year flood year flood C-year flood 4 8 U HORZONTAL SCALE, N FEET 4 CROSS SECTON CROSS SECTON 27 too FGURE 5aScholfield Creek cross sections 72

78 4 Left bank \ := 1 \ V CROSS SECTON CROSS SECTON 29 V too o r \ U too 3 CROSS SECTON vcc mbined will 1 year fload EXPLANA11ON 5year flood looyear flood 25-year flood year flood 4 6 HORZONTAL SCALE, N FEET CROSS SECTON too 'LU f\ Cornbned with year flood 2.iamnu with t.it year TOt CROSS SECTON CROSS SECTON 32 FGURE53--Scholfield Greek cross sections

79 Loll bank 1 3 Rght bor wilh year flood 4 CROSS SECTON lao LU _J 4 J uj CROSS SECTON TOO U EXPLANATON 5-year flood 1-year flood 25-year flood 1-year flood 4 8 HORZONTAL ScALE. N FEET CROSS SECTON

80 3 Loft book book CROSS SECTON Ui CROSS SECTON 6 8 Ui > 8 2 -v! : 3 2 CROSS SECTON EXPLANATiON 5-year flood 1-year flood 25-year flood 1-year flood CROSS SECTON HORZONTAL SCALE, N FEET FGURE 55--Smith River cross-sections 75

81 Left bank Rih blink 1 2 CROSS SECTON EXPLANA11ON 5year flood looyear flood 25-year flood CROSS SECTON ORZONTEL SCALE N FEET 2 CROSS SECTON OD CROSS SECTON FGURE 56--Smith River cross-sections 76

82 L2f 3 Rh bank 2 1 EXPLANATON 5-year flood OOyear flood year flood year flood CROSS SECTON : HORZONTAL SCALE, N FEET CROSS SECTON a L r ij 1 J -2 1 '? CROSS SECTON 11 CROSS SECTON V \ \ CROSS SECTON 13 CROSS SECTON H FGURE 57--Smith River cross-sections 77

83 Left bank 3 Right bank 3 Left bank Atgh? bank CROSS SECTON 15 CROSS SECTON J w -J () lj - w CROSS SECTON \ 4 2 CROSS SECTON 18 CROSS SECTON EXPLANATON 5-year flood -year flood 25-year flood -year flood 8 HORZONTAL SCALE, N FEET C CROSS SECTON 2 CROSS SECTON 21 FGURE 58--Smith River cross-sections 78

84 Lftft bo V 'f 2 CROSS SECTON J LjJ > 1 CT) w Q CROSS SECTON q 18 Li 2 1 V CROSS SECTON C) -1 2 CROSS SECTON EXPLANATON SOOyear flood OOyeor flood a-year flood O-ye flood 4 8 HORZONTAL ScALE, N FEET FGURE 59.Smith River cross-sections 79

85 Left book 3 Right bank 3 Left bank Right bank 2 to a CROSS SECTON CROSS SECTON U CROSS SECTON 'O 2 CROSS SECTON 29 6* \ \ -1 \1, SOC CROSS SECTON 3 CROSS SECTON EXPLANATON SOO-year flood 1 1 looyear flood 25-year flood -year flood HORZONTAL SCALE, N FEEr CROSS SECTON 32 CROSS SECTON 33 FGURE 6--Smith River cross-sections 8

86 Left bank Right bank Left hank 3 r 3r- book 2 2 \ CROSS SECTON CROSS 3 2 SECTON 35 6 aoo CROSS SECTON CROSS SECTON 3? = CROSS SECTON 38 L CROSS SECTON fo o C ) CROSS SECTON 2 6 EXPLANA11ON 5-year flood - OOyear flood 25-year flood -year flood 4 8 HORZONTAL SCALE, N FEET 1 FGURE 61--Smith River cross-sections 81

87 Loft b RiQhf bmk Left bor Rigf bor J 4.- J C CROSS SECTON 3 2 eoo % CROSS SECTON '2 2 2 w _J 1 1 w Cl) w uj > 4 F- LiJ t 1Q CROSS U _ i$ CROSS SECTON SECTON CROSS SECTON 45 CROSS SECTON EXPLANATON 5-year flood 1-year flood 25-year flood -year flood 4 8 HORZONTAL SCALE, N FEET FGURE 62 --Smith River cross-sections 82

88 Left bank 3 r- int bank Left bank Right bcnk iao 2 2 t CROSS SECTON ' CROSS SECTON J LU j LU LU > 2U 2 CROSS SECTON (J -1 U 2 2 CROSS SECTON \ CROSS SECTON 51 Q CROSS SECTON EXPLANA11ON 5year fod 1-year flood 25-year flood 1-year flood 4 8 HORZONTAL SCALE, N FEET oa CROSS SECTON 53 FGURE 63Smith River cross-sections 83

89 Left bank 4 Right bank 4 Left bank fl,çht bank C -1 : -2 2 JU > U (, CROSS SECTON 54 CROSS SECTON J U -1 1 Li_ - > U CROSS SECTON 56 L CROSS SECTON 5? 4 3 o 1 2 ) CROSS SECTON O 1 U C EXPLANATON 5-year flood 1-year flood 25-year flood 1-year flood 2 CROSS SECTON HORZONTAL SCALE, N FEET FGURE 64--Smth River cross-sections 84

90 Left bank R9ht bank 4 Left bank Right bank CROSS SECTON CROSS SECTON CROSS SECTON CROSS SECTON EXPLANATON 5year flood OOyear flood 25-year flood JO-year flood CROSS SECTON 64 HORZONTAL SCALE, N FEET FGURE 65Smith River cross-sections 85

91 Left book RQN bor* Loll bank Rht bank J CROSS SECTON CROSS SECTON J 2 Ui 2 _J 1 1 LU LU U -1 \ 2 CROSS SECTON 68 - LiJ CROSS SECTON 6? N CROSS SECTON 69 CROSS SECTON 7 EXPLANA1JON 5OOear fbod OOyear flood -year flood -year flood 4 8 HORZONTAL SCALE. N FEET FGURE 66.Smith River cross-sections 86

92 4 Left n Rghl bik 4 Left bank Right honk CROSS SECTON CROSS SECTON _ lii -1 2 COO 1 W CROSS SECTON 73 : CROSS SECTON 74 1 V N ' CROSS SECTON 75 CROSS SECTON 76 EXPLANATON 5-year flood 1-year flood 25-year flood 1-year flood 4 8 HORZONTAL SCALE, N FEET FGURE 67--Smith River cross-sections 87

93 Left bank Right bank Left bank Right honk Left bank Right bank r CROSS SECTON CROSS SECTON \J CROSS SECTON \ V n 2 6 CROSS SECTON CROSS SECTON 81 CROSS SECTON ) eoo 1 CROSS SECTON CROSS SECTON 84 EXPLANATON 5OOyear flood OOyear flood 25-year flood -year flood 4 8 HORZONTAL SCALE, N FEET FGURE 68--Smith River cross-sections 88

94 4 Left bon F4ght bn 4 Left bk Right txo* A) CROSS SECTON CROSS SECTON 85 da C. 2 V CROSS SECTON 87 4 J CROSS SECTON \ 3 1 \' \ CROSS SECTON 89 CROSS SECTON 9 EXPLANATON 5yeor flood 1-year flood 25-year flood -year flood 4 8 HORZONTAL SCALE, N FEET FGURE 69--Smith River cross-sections 89

95 L1 bank 5 gh bank 5 Left bank Righ? bank Left bank Right bank Cl 1 1 Ci CROSS SECTON 91 CROSS SECTON 92 CROSS SECTON 93 EXPLANATON SOC-year flood 1-year flood 25-year flood 1-year flood 4 HORZONTAL SCALE, N FEET FGURE 7--Smith River cross-sections 9

96 Lo'l book 13 Sc Rçht b* 13? 13 Sc CROSS SECTON J 13 5 EXPLANATON OO flood 13? -year flood 25-year flood 1-year flood w water 4 HORZONTAL SOALE N FEET CROSS 2 SECTON lo JJ 13 9 uj > CROSS 14 2 SECTON ? 13? CROSS SECTON 4 CROSS SECTON CROSS SECTON 6 FGURE 71 --Cow Creek CrOSS-SeCTOnS 91

97 Left bort 14 Right bank Left bor* 14 Right bank CROSS SECTON CROSS SECTON r,1 EXPLANATON 5-year flood -year flood 25-year flood 1-year flood Low water HORZONTAL SCALE, N FEET 136 CROSS SECTON CROSS SECTON tco CROSS SECTON CROSS SECTON CROSS SECTON *2 FGURE 72--Cow Creek cross-secfions 92

98 Lot? bank Right bank Left benk Right honk 7 13? SO: CROSS SECTON 14 CROSS SECTON C ood CROSS SECTON 16 CROSS SECTON w w > 8 : o 13? boo 14 :: - = CROSS SECTON 18 2q 26 EXPLANAflON 5-yeor flood year flood year flood 1-year flood Low water 4 8 HORZONTAL SCALE, N FEET CROSS SECTON q CROSS SECTON 2 FGURE 73--Cow Creek cross-sections 93

99 Lat bonk Rihl book 141 Loft booth CROSS SECTON 21 CROSS SECTON CROSS SECTON 23 CROSS SECTON u LU > CROSS SECTON 'U CROSS SECTON CROSS SECTON EXPLANATN 5-year flood 1-year flood 25-year flood 1 year flood Low water HORZONTAL SCALE, P9 FEET CROSS SECTON 28 AGURE 74--Cc Creek cross-sections 94

100 RM Let bcnk 14 3 i' CROSS SECTON CROSS SECTON EXPANA11ON 5-year flood CROSS SECTON 31 -\ year flood 1 year flood Low water HORZONTAL SCALE, 14 FEET CROSS SECTON it 1 2 CROSS SECTON CROSS SECTON CROSS SECTON CROSS SECTON FiGURE 75.--Ccw Creek c,ss-secfions 95

101 Left book 145 Right bank Left $ Rght bait 145Lett 145 $ Rtqht bart $ 142 CROSS SECTON 37 CROSS SECTON 38 CROSS SECTON $ C C $ J uj CROSS SECTON w () 144 L1J CROSS SECTON ! CROSS SECTON C \ ' CROSS SECTON 43 CROSS SECTON Q FGURE 76--Cow Creek cross-sections 96 EXPLANATON 5-year flood 1-year flood 25-year flood -year flood Low water HORZONTAL SCALE. N FEET SO

102 Right borlk CROSS SECTON CROSS SECTON L' ELEVAT ON, N FEET ABOVE MEAN SEA LEVEL q C 2 CROSS SECTON CROSS SECTON '18 -S A NY 1' CC y CROSS SECTON 19 FGURE 7--Cow Creek CrOSS-SeCtionS 97

103 Left book 148 R,qhl bank CROSS SECTON q CROSS SECTON CROSS SECTON CROSS SECTON $ EXPLANATON 5-year flood -year flood 25-year flood 1-year flood Low water 4 8(?O HORZONTAL SCALE f FEET FGURE 78--Gc Greek cross-sections 98

104 9Left b Jgh br6 14 EXPLANAtiON 5-year flood year flood 25-year flood -year flood 14 7 Low water 14 CROSS 149 SECTON l KRZONT4L 1 F, N FEET _ CROSS SECTON V\ V \\ ( 148 ljj > LiJ CROSS SECTON 56 2 is - Z N. '7 14 v _1' CROSS SECTON 5? CROSS SECTON L CROSS SECTON CROSS SECTON HGURE 79--Cow Creek cross-sections 99

105 CROSS SECTON CROSS SECTON CROSS SECTON CROSS SECT TON q 82 CROSS SECTON CROSS SECTON CROSS SECTON EXPLANATON 5-year flaad -._._._._.. 1-year flaod 25-year flood 1-year flood Low water 15 2 CROSS SECTON B 22 o 4 8 HORZONTAL SCALE, N FGURE 8--Cow Creek cross-sections

106 l.eft bapa 154 Right nk B 8 22 CROSS SECTON CROSS SECTON 7 CROSS SECTON w > q 1 14 CROSS SECTON 72 CROSS SECTON q CROSS SECTON 74 CROSS SECTON U 157 EXPLANATON 5-year flood LL _ year flood 25-year flood 1-year flood CROSS SECTON 71 CROSS SECTON 77 i Low water HORZONTAL SCALE, N FEET BOO CROSS SECTON 78 CROSS SECTON 79 FGURE 81--Cow Creek cross-sections

107 8Left bonk 15 Ri48? borá CROSS SECTON boo CROSS SECTON CROSS SECTON a C 157 \ N N CROSS SECTON CROSS SECTON * 22 CROSS SECTON Li EXPLANATON 5year flood CC-year f load 25-year flood 1-year flood Low water HORZONTAL SCALE, N FEET CROSS SECTON * FGURE 82--Con Creek cross-sections 12

108 16Left bank Right bank 16Lefl bank Rgot book L9H book 16 Right bank : CROSS SECTON 88 CROSS SECTON boo CROSS SECTON CROSS SECTON 9 CROSS SECTON J LU LU 159 C L CROSS SECTON 32 CROSS SECTON CROSS SECTON 95 CROSS SECTON jw 15 9 boo CROSS SECTON 16 9' S 1 moo CROSS SECTON 98 CROSS SECTON CROSS SECTON 97 EXPLANATON 5-year flood 1-year flood 25-year flood -year flood Low water HORZONTAL SCAL.E, 4 8 FEET FGURE 83--Cow Creek cross-sections KJ3

109 CROSS SECTON 1 6 CROSS SECTON ) CROSS SECTON CROSS SECTON CROSS SECTON ? 16? uj uj > CROSS 2 SECTON CROSS SECTON ' ? 167 1: CROSS SECTON CROSS SECTON 1? CROSS SECTON EXPLANATON 5-year flood -. _._._ year flood 25-year flood _--_-._._.-._ 1-year flood Low water 16? CROSS SECTON HORZONTAL SCALE. N FEET 166 CROSS SECTON 11 4 riue 84--Cow Creek cross-sections 4

110 Left bank Rçh? bank Left book Right bank Left b,ok C RFght bank 'F 'F 16 J 8 w N ,-wji ci CROSS SECTON 116 CROSS SECTON J 173 C ? 3 w Ui Lii > U 17 - Lii Q C J l.lj CROSS SECTON 18 CROSS SECTON i CROSS SECTON 112 CROSS SECTON CROSS SECTON 167 CROSS SECTON 113 CROSS SECTON 12 1 H CROSS SECTON 121 CROSS SECTON EXPLANATON 5-year flood year flood year flood 1-year flood U 174 Low water ?i 1? q 6 HORZONTAL SCALE, N FEET CROSS SECTON 127 1? 2 2 CROSS SECTON oo CROSS SECTON CROSS SECTON CROSS SECTON FGURE 95--Cow Creek Cross-sections 5

111 L&l bc Right bank Lett bano Righi bank tfl bank U J CROSS SECTON CROSS SECTON 129CROSS SECTON ( CROSS SECTON a _ uj LU CROSS SECTON 132 CROSS SECTON CROSS SECTON 134 CROSS SECTON CROSS SECTON 136 CROSS SECTON 137 F LU CROSS SECTON CROSS SECTON 139 CROSS SECTON CROSS SECTON CROSS SECTON EXPLANATON 5O flood 183 -year flood 25-year flood - 1-year flood 182 Low water 2 CROSS SECTON 144? i HORZONTAL SCALE, J FEET 8?O CROSS SECTON 142 FiGURE 86--Cow Creek cross-sections 6

112 Left bank ht barb 7Lft bonk Right bank Left bank Right bank Lf bank Right bank U C CROSS SECTON 147 CROSS SECTON CROSS SECTON CROSS SECTON _ CROSS 2 SECTON 15! CROSS SECTON 152 () Ui CROSS SECTON CROSS SECTON o CROSS SECTON CROSS 2 SECTON CROSS SECTON CROSS SECTON Lii t CROSS SECTON 157 CROSS SECTON 158 CROSS SECTON EXPLANATON 5-year flood year flood 25-year flood 1-year flood Lowwoter CROSS 1 SECTON CROSS SECTON 162 CROSS SECTON C' 2 62 CROSS SECTON ORZONTAL Al F, N EET FGURE 87--Cow Creek cross-sections 17