or14001_Drainage Report.pdf

WESTERN FEDERAL LANDS HIGHWAY DIVISION

VANCOUVER, WASHINGTON

OR DOT 140(1)

Klamath County Boat Marina to Lakeshore Drive

Drainage Report

95% PS&E

ii

Table of Contents

INTRODUCTION

EXISTING CONDTIONS

Topography

Existing Drainage Patterns

Existing Culverts - Lake Section

Water Surface Elevation

Soils

Critical Areas

Critical Species

PROPOSED CONVEYANCE SYSTEM ANALYSLIS AND DESIGN

Culvert Conveyance

Ditch Conveyance

PROPOSED STORMWATER TREATMENT FACILITIES

Hydrology

Lake Section

Land Section

BIOFILTRATION SWALES

Hydrology

Check Dams

Riprap Erosion Control

SUMMARY

Appendix A: Capacity Analysis

Appendix B: CIA Maps

Appendix C: Soils

INTRODUCTION

The Federal Highway Administration (FHWA) and the Oregon Department of Transportation (ODOT) are jointly proposing a project to modernize Oregon Route 140 – Lake of the Woods Highway (OR 140) to accommodate future traffic volumes and opportunities for bicycle use.

OR 140 is a state highway that traverses the southern portion of the state of Oregon. This project takes place on a segment of road that runs between the cities of Klamath Falls and Medford with a current seasonal ADT of 2700 and 28% truck traffic. The highway is a designated freight route between Medford and Lakeview. The project is located approximately 5 miles west of the city of Klamath Falls, which is part of the Volcanic Legacy Scenic Byway.

The route provides access to the Fremont-Winema National Forest, Rogue Siskiyou National Forest, BLM Lands, Upper Klamath Lake and various recreational facilities. The route also provides access to public and private timber lands, residential property, and can be used as an alternate route to Crater Lake National Park. For a portion of the project corridor, the roadway runs adjacent to Upper Klamath Lake.

The existing roadway (travel lanes and shoulders) is too narrow to accommodate current and future traffic volumes and doesn’t provide opportunities for bicycle use. This causes a severe safety concern for the traveling public. In addition, there are no existing protective measures to prevent vehicles from leaving the highway and going into the lake.

The project improvements include widening the roadway to 12-foot travel lanes with 6-foot shoulders and realignment where necessary. Construction will require new embankments fills within Upper Klamath Lake to allow for widening and construct and/or armor the embankments with stone or riprap to prevent wave erosion. Additional project elements are:

stormwater treatment wetland mitigation guardrail high performance pavement markings shoulder and center-line rumble strips additional parking facilities along the lake fish enhancement features within the stone embankment fills in the lake

This memorandum provides a summary of the water quality treatment for the 70% design and should be reviewed concurrently with the preliminary design plan set. Elevations used in this report are referenced to the project datum (North American Vertical Datum 1988; NAVD88);

which is 1.8 feet higher than the Reclamation’s datum for the upper Klamath Basin.

EXISTING CONDTIONS

OR 140 is a unique project that includes existing natural features that will require creative solutions to design, permit and construct. The overall project is approximately 6-miles long, with the first 2-miles adjacent to Howard Bay on Upper Klamath Lake (Lake Section). The remaining 4-miles are in the upland section (Land Section). The natural conditions include topography, existing drainage, lake water surface elevation, critical wetland and waterway areas, and endangered species. Below is a brief explanation of the existing conditions:

Topography At the beginning of the project, at the base of Doak Mountain, the roadway levels off at elevation 4,150-ft. The next 2-miles across the lake are very flat with a longitudinal slope of 0.0%. This section of roadway was originally constructed in fringe wetlands and today acts as a dike in some locations. Adjacent to the Lake Section of roadway is a steep east facing slope.

The elevation at the top is approximately 5,047-ft and common slopes in this hillside are 1V:1.3H.

As the roadway ascend the Lake Section (STA 155+00) it travels through a cut-section to the uplands. The elevation of the roadway starts at 4,148-ft and peaks at elevation 4,250-ft. The gradient in this section is 5.4%. The road then gradually declines to an elevation of 4,150-ft with grades between 0.9% and 3.1% to the intersection with Lakeshore Drive.

Existing Drainage Patterns The Lake Section drains directly to Upper Klamath Lake or roadside wetlands and ditches depending on which direction the road surface slopes. The lake and roadside wetland/ditches are hydraulically connected by Geary Canal, cross culverts, and groundwater flow through the road embankment.

The Land Section generally slopes from northeast to southwest. Existing roadside ditches and cross culvert collect and convey stormwater runoff to the south side of the roadway. Existing drainageways convey stormwater to adjacent fields before ultimately discharging to a canal systems located south of the project.

Existing Culverts - Lake Section Within the limits of the Lake Section there are 4 existing culverts. All these culverts are 18-inch diameter and connect the roadside ditches to Upper Klamath Lake. At stations 25+50 and 44+25, wetlands have developed at the inlet side, which may indicate that the culverts are undersized or have long periods of standing water. This may also be a result of being in a tailwater condition of Upper Klamath Lake during winter/spring months when the lake is at its highest water surface elevation for water storage. The culverts are being replaced to extend the service life of the road and improve the hydraulic performance.

Water Surface Elevation Upper Klamath Lake is owned and operated by the Bureau of Reclamation to support irrigation for agricultural uses. The lake water surface elevation is controlled by the Link River Dam, which generally has a maximum water surface elevation of 4,145.1-feet. The road elevation is generally 4,150-feet.

Soils The Natural Resource Conservation Service (NRCS) maps indicates the site to be predominantly underlain by the following soils:

Figure 1: NRCS Soils Map

1—Algoma silt loam, MLRA 21 Hydrologic Soil Group: C/D Capacity of the most limiting layer to transmit water (Ksat): Moderately low to moderately high (0.06 to 0.20 in/hr) Natural drainage class: Poorly drained

50E—Lorella very stony loam, 2 to 35 percent south slopes--Hydrologic Soil Group:

DCapacity of the most limiting layer to transmit water (Ksat): Moderately low to moderately high (0.06 to 0.20 in/hr) Natural drainage class: Well drained

81 E - Woodcock association, north Hydrologic Soil Group: B Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.57 to 1.98 in/hr) Natural drainage class: Well drained

82 E - Woodcock association, south Hydrologic Soil Group: B Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.57 to 1.98 in/hr) Natural drainage class: Well drained

83F - Woodcock-Rock outcrop complex, 40 to 60 percent north slopes Hydrologic Soil Group: B Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.57 to 1.98 in/hr) Natural drainage class: Well drained

These soils are classified as well drained, expect Algoma silt loam which is located at the end of the project. Aerial photography supports the poorly drained classification because the area appears to have greener vegetation. Based on the other soils capacity to transmit water, the water quality design storm should infiltrate.

Critical Areas Upper Klamath Lake is the largest body of fresh water by surface area (61,543 acres) in Oregon. Its approximately 25-miles long and 8-miles wide. The lake is fed by a watershed of 3,768 square miles which includes the Williamson and Wood Rivers. Below the Link River Dam water drains through Lake Ewauna before discharging into the Klamath River. Today, the historic wetland complexes in this system have been severally degraded by the construction of the Link River Dam and farming. The wetlands and marshes have either been converted to reservoir or drained for farmland.

This project is proposing to construct roadway embankment fill in Upper Klamath Lake and several low-quality wetlands. To determine the size and classification of the existing wetlands, wetland delineations were completed by SWCA Environmental Consultants. Wetlands will be avoided, where feasible. However, there will be minor wetland impacts. To mitigate for wetland and habitat impacts, this project will enhance the lake shore onsite with native plants.

Critical Species Several important species are documented within the project limits. Bald Eagles, Golden Eagles, Lost River sucker and shortnose sucker fish are major factors in the design and construction of this project. Documented eagle nests are located along the steep slopes overlooking Howard Bay. Further documentation will be collected during the design of this project per the Bald and Golden Eagle Protection Act.

In 1988, the Lost River sucker and shortnose sucker was added to the Endangered Species Act of 1973 due to plummeting population caused by loss of habitat due to dam creation, agriculture and poor water quality. Upper Klamath Lake contains Lost River sucker and Howard Bay is mapped as critical juvenile sucker habitat.

PROPOSED CONVEYANCE SYSTEM ANALYSLIS AND DESIGN

The proposed drainage improvements associated with this project will include roadside ditches and cross-culverts. The drainage system will convey runoff directly to Upper Klamath Lake, which is the largest lake in Oregon. Per the FLH PDDM cross-culverts are recommended every 500-feet. This project follows the general spacing guideline and adds 24-inch diameter culverts. The capacity of the system was analyzed to confirm pipe culvert spacing meets design criteria. Per Chapter 3 of ODOT’s Hydraulics Manual (2014 Version), the design recurrence interval for ditches and storm drains is 10-year event. Storm drain outfalls in sags have a design recurrence interval 50-years for roads with ADT greater than 750. OR 140 is flat and has an ADT of 3024 vehicles. Therefore, the proposed drainage improvements were designed to meet the hydraulic capacity for the 50-year rainfall event.

Culvert Conveyance The site is located within the jurisdiction of the Oregon Department of Transportation (ODOT). The guidelines used for the design of this project reflect ODOT’s standards as described in Chapter 7 of ODOT’s Hydraulics Manual (2014 Version). The project resides within climate region 4

The Rational Method was used to calculate peak flows and analyze culvert capacity. Basins were delineated based on the PDDM guidelines at approximate 500-foot intervals. All the drainage areas were less than 200-acres and Basin 7 is the largest with 29-acres. Basin 7 was the only one analyzed because all the others are smaller and established a peak flow that was assumed for each basin within the Lake Section.

The 50-year and 100-year storm event was determined by using the NOAA Atlas 2 Precipitation Frequency Estimates. The 50-year storm event was used as the peak capacity for each culvert/ditch to ensure no roadway flooding occurs.

FHWA Hydraulic Toolbox 4.2 was used to compute time of concentration and runoff rates.

The contributing area land cover is forest with steep slopes. The Runoff coefficients were selected based on site visits and aerial photography. In addition, the culvert capacity was designed with no headwater (HW<D).

The culverts discharging into Upper Klamath Lake will be under backwater conditions during design flow events. Therefore, the HY8 computer program was used to design the culvert pipes. The maximum operating water surface elevation of 4145-ft (NAVD-88) was used as a fixed tailwater elevation in the backwater analysis. The results of the pipe culvert capacity analysis are included in Appendix A

No roadway flooding occurs.

Ditch Conveyance FHWA Hydraulic Toolbox 4.2 was used to compute the ditch capacity. A triangular shaped ditch with 1V:1H side slopes, longitudinal slope of 0.4% and Manning’s roughness coefficient of 0.033 (Chow, 1959) was analyzed. The depth of flow resulted in 0.73-feet and 0.81-feet for the 50-year (6.8 cfs) and 100-year (9 cfs) flows, respectively.

PROPOSED STORMWATER TREATMENT FACILITIES

The intent of the project’s stormwater quality facilities is to treat all the contributing impervious area within the reconstructed sections, which is approximately 20.5 acres. This is a significant improvement to the treatment currently provided. The roadway areas that are only overlaying the existing asphalt will continue to drain as to pre-project conditions. The attached Contributing Impervious Areas figure documents the catchment areas (CIA). In addition, Table 1 shows BMP selected for treatment.

Hydrology The Santa Barbara Unit Hydrograph (SBUH) Method and NRCS Type 1 rainfall distribution (Central Oregon Stormwater Manual) were utilized to calculate water quality flows. Per the ODOT Hydraulics Manual, the water quality design storm is 50% of the cumulative rainfall from the 2-year, 24-hour storm which is 1.69-inches of rainfall in a 24-hour time-period for this project location (Oregon GEO, 2015). Therefore, the cumulative rainfall water quality design storm is 0.85-inches.

Lake Section The existing conditions and environmental constraints surrounding this site make it the ideal candidate for a context sensitive design requiring a holistic approach. Applying mitigation requirements to fully meet the different federal and state agencies will create conflicting impacts. For example, if construction of water quality facilities in Upper Klamath Lake are required to fully meet the ODOT Hydraulics Manual; either additional fill within Upper Klamath Lake or excavation into the hillside is required. Both actions have environmental impacts.

Fill within Upper Klamath Lake will decrease the lake surface area, kill suckers and other aquatic species, and impact water quality by increasing turbidity. These activities require additional mitigation from the following agencies for the habitat, wetland, and waterway impacts:

U.S. Army Corps of Engineers U.S. Fish and Wildlife Service

U.S. EPA

Oregon Department of State Lands Oregon Department of Fish and Wildlife Oregon Department of Environmental Quality

Figure 2: Rockfall Protection on Oregon State Route 97

Avoiding the lake impacts would require excavation into the hillside. This action could also have major environmental and safety impacts. The hillside adjacent to Howard Bay consist of large boulders and steep terrain. If the base of the hillside is disturbed by excavation, the construction would create an unstable condition resulting in landslides.

Similar geologic features have been disturbed by roadway construction in the Klamath County area. One example is located across the lake on nearby Oregon route 97 (see Figure 2). Road construction removed native vegetation and cut into the hillside. Today the cut slopes are unstable and eroding creating safety concerns. In some areas rockfall protection mitigation has been installed, but rocks still fall onto the roadway requiring regular maintenance.

If the hillside became unstable in this project location there would be a significant safety concern for falling rocks. In addition, there would be potential for losing critical eagle habitat along the hillside. Therefore, this project is not proposing to cut into the hillside, but rather fill into the lake and provide water quality to the maximum extent practicable.

The Lake Section runoff will be treated with biofiltration BMPs, which are effective for removal of total suspended solids/turbidity. Along the lake frontage, Vegetated Filter Strips (VFS) will be designed to meet the minimum dimension (5-ft) outlined in the ODOT Hydraulic Manual. The size was selected based on minimum widths required to treat surface runoff from the pollution generating impervious surface from centerline to the edge of pavement (20-ft).

Where the roadway has superelevation the VFS will not meet the full level of water quality treatment, but will be an improvement from the existing conditions and minimize impacts the other environmental resources. The length of VFS to fully treat 40-ft of pavement is 10-ft at 2% cross slope. The additional fill and surface area impacts for the 10-foot VFS on Upper Klamath Lake are estimated to be 28,150 CY and 1.75 acres, respectively.

Figure 3: Cross-Section comparison between 5-foot VFS and 10-foot VFS

Land Section The primary water quality approach for the Land Section is to disperse stormwater runoff into adjacent areas wherever feasible or construct biofiltration BMPs in the ditches. The Land Section is generally located in upland surrounded by undeveloped areas. A zoning map is shown below and identifies primary land uses as Forest/ Range and Exclusive Farm Use. In addition, the soils are generally defined as well drained by the NRCS soils maps. These conditions are well suited for dispersion BMPs.

Figure 4: Klamath County Zoning Map

The Washington Department of Transportation (WSDOT) Hydrologic Runoff Manual (HRM) and a California Department of Transportation (CalTRANs) study were referenced in the design of the dispersion areas.

The WSDOT HRM recommends two options for sites east of the cascades. The first option outlines site specific criteria to calculate a dispersion distance. Option 2 uses a generalized approach that indicates natural dispersion will occur with 100-feet of the roadway; and therefore, natural resources must not be within 100-feet.

The CalTRANs study concluded that non-engineered vegetated areas along highways have performance comparable to systems engineered and operated specifically for water quality improvement. The following buffer strips widths are recommended for the removal of storm water contaminants:

14-feet for slopes less than 10% (1:10) 15-feet for slopes greater than 10% and less than 35% (1:10 to 1:2.9) 30-feet for slopes between 35% and 50% (1:2.9 to 1:2)

The dispersion areas for this project have length greater than 15-ft with the right-of-way and greater than 100-ft to the nearest waterway or wetland. Therefore, the water quality design storm will be treated in the proposed dispersion areas.

BIOFILTRATION SWALES

The biofiltration swales were designed to slow the velocities as well as provide an area for flows to infiltrate the runoff. The biofiltration swales follow the ODOT Hydraulic Manual guidelines. The swales are designed to have a 4-foot flat bottom width. Having a large flat bottom increases surface area and contact that the runoff will have with the water quality soil to increase infiltration potential. The biofiltration swales are designed to have 18-inches of water quality soil that is designed to infiltrate and trap pollutants. The runoff needs enough time within the biofiltration swale to provide the opportunity for pollutant removal through the water quality soil. The time spent within the biofiltration swale is the residence time and the ODOT Hydraulics Manual specifies a minimum of 9-minutes to effectively treat the stormwater. The biofiltration swales were designed to have a minimum hydraulic residence time of 9-minutes during the water quality storm event. Check dams are also proposed within the water quality swales to further slow flows and increase treatment as well as to provide detention.

Hydrology The Santa Barbara Unit Hydrograph (SBUH) Method and NRCS Type 1 rainfall distribution (Central Oregon Stormwater Manual) were utilized to calculate water quality flows. Per the ODOT Hydraulics Manual, the water quality design storm is 50% of the cumulative rainfall from the 2-year, 24-hour storm which is 1.69-inches of rainfall in a 24-hour time-period for this project location (Oregon GEO, 2015). Therefore, the cumulative rainfall water quality design storm is 0.85-inches.

Table 1: Water quality flow and treatment BMP

Catchment Station Start

Station End

Length (ft)

Area

(SF)

Flow (cfs)

Treatment BMP

A 18+05 22+00 395 13,228 0.2 Bioswale

B 22+00 64+40 4240 155,521 Vegetated Filter Strip**

C 45+53 54+11 858 14,969 0.2 Bioswale

D 62+41 85+44 2303 78,058 1.1 Bioswale*

E 72+34 75+80 346 6,277 Vegetated Filter Strip**

F 82+36 99+91 1755 53,850 Vegetated Filter Strip**

G 92+43 107+93 1550 36,108 0.5 Bioswale

H 103+79 110+08 629 17,466 Vegetated Filter Strip**

I 115+00 134+67 1967 35,056 Dispersion / Overlay

J 110+08 156+98 4690 130,405 Dispersion / Overlay

K 147+50 156+98 948 17,038 Dispersion

L 156+98 163+00 602 11,231 Dispersion

M 156+98 162+50 552 9,941 Dispersion

N 163+00 180+04 1704 30,674 0.4 Bioswale

O 162+50 183+00 2050 36,900 0.5 Bioswale

P 183+00 190+25 725 13,046 Dispersion

Q 180+04 225+26 4522 109,047 1.5 Bioswale*

R 205+60 225+26 1966 35,392 Dispersion

S 225+26 240+70 1544 27,780 0.4 Bioswale

T 225+26 236+50 1124 20,213 Dispersion

U 236+50 244+00 750 19,445 0.3 Bioswale

V 244+00 257+84 1384 40,460 Dispersion

W 252+63 257+84 521 9,368 0.1 Bioswale

X 257+84 271+46 1362 24,500 Vegetated ditch

Y 257+54 287+25 2971 75,491 1.0 Bioswale

Z 284+00 290+15 615 11,093 0.2 Bioswale

AA 287+25 306+10 1885 33,930 Dispersion

AB 290+15 319+60 2945 95,922 1.3 Drains to retention area

* Substandard bottom width ** Substandard width

Check Dams Check dams are proposed to reduce the energy grade line and slow water flowing in ditches.

This reduces ditch and shoulder erosion, and encourages infiltration and sediment deposition.

Check dams are located at existing drainage ditches immediately adjacent to the roadway and at roadside ditches with moderately steep slopes. Six check dams are proposed on attached site sketches. Typical details are also attached.

Riprap Erosion Control Controlling erosion at culvert outlets, culvert inlets, and within roadside ditches is essential for reducing the amount of sediment released with the stormwater discharge. Riprap splash pads are proposed at outlets of all minor drainage culverts. Along the lake riprap is proposed for roadway embankment and protection. Typical splash pad details are attached.

Riprap lined ditches are proposed when ditch slope is greater than 4 percent and where installing additional cross drainage culverts is not practicable. Proposed riprap erosion controls are shown on site sketches.

SUMMARY

The stormwater treatment proposed for this project provides pollutant removal to the maximum extent practicable while minimizing disturbance of Upper Klamath Lake. The proposed treatment facilities promote the use of dispersion areas and native soils which would be required to construct additional stormwater treatment facilities. Constructing biofiltration swales and optimizing ditch relief culverts encourages infiltration, sedimentation, and filtration, as well as avoids direct discharge from high sediment areas. Bioswales and vegetated filter strips utilize infiltration, filtration, sorption, hydraulic attenuation, and density separation for treatment. Check dams encourage infiltration and sediment deposition as well as reduces erosion. Riprap splash pads and linings reduce erosion.

Appendix A: Capacity Analysis

Figure 1: Basin Map

Figure 2: Basin Map

Hydraulic Analysis Report Project Data

Project Title: Project - OR 140 Designer:

Project Date: Monday, September 30, 2019 Project Units: U.S. Customary Units Notes:

Rational Analysis: Rational Method Analysis, 25YR Notes:

Rational Method Input Parameters Runoff Coefficient: 0.20 Basin Area: 30.0000 acres Rainfall Intensity: 1.13 in/hr Time of Concentration: 28.63 minutes Recurrence Year: 25 year

Rational Method Results Flowrate: 6.8 cfs

IDF Input Parameters NOAA Atlas Data State: Oregon Region: Region 4 2 yr, 6 hr: 0.7000 in 2 yr, 24 hr: 1.4000 in 100 yr, 6 hr: 1.5900 in 100 yr, 24 hr: 2.8100 in

IDF Results 25 year IDF equation: i = 19.1581 / (Tc + 9.13962)^0.779343 Intensity: 1.1304 in/hr

Time of Concentration Input Parameters Computed Time of Concentration Time of Concentration: 28.63 min

Sheet Flow Input Parameters Top Elevation: 4991.00 ft Bottom Elevation: 4980.00 ft Length: 150.00 ft Recommended length not to exceed 30 m. Maximum length is 90 m Manning's n: 0.4000

Rational Analysis: Rational Method Analysis, 25YRRational Analysis: Rational Method Analysis, 25YR

Basin Area: 30.0000 acres

Flowrate: 6.8 cfs

Basin 7 has the largest drainage area at 29 acres. For the conveyance capacity analysis, all basins are assumed to be 30 acres.

See HDS-2 Table 2.1 2 yr, 24 hr precip: 1.4000 in

Sheet Flow Results Slope: 0.0733 ft/ft Time of Concentration: 26.70 min

Shallow Concentrated Flow Input Parameters Top Elevation: 4980.00 ft Bottom Elevation: 4280.00 ft Length: 1540.00 ft k: 0.6000 See HDS-2 Table 2.2

Shallow Concentrated Flow Results Slope: 0.4545 ft/ft Velocity: 13.3492 ft/s HDS-2 equation 2.7 Time of Concentration: 1.92 min

Total Time of Concentration Time of Concentration: 28.63 min

Hydrograph - Rational Method Analysis, 25YR - Rational Hydrograph Method 25 year recurrence Interval, Peak Discharge: 6.839 cfs, Time to Peak: 28.00 (min), Total Volume:

11368.24 ft^3

Time (minutes) Flow cfs

0.00 0.00

1.00 0.24

2.00 0.48

3.00 0.72

4.00 0.96

5.00 1.19

6.00 1.43

7.00 1.67

8.00 1.91

9.00 2.15

10.00 2.39

11.00 2.63

12.00 2.87

13.00 3.11

14.00 3.34

15.00 3.58

16.00 3.82

17.00 4.06

18.00 4.30

19.00 4.54

20.00 4.78

21.00 5.02

22.00 5.26

23.00 5.49

24.00 5.73

25.00 5.97

26.00 6.21

27.00 6.45

28.00 6.84

29.00 6.59

30.00 6.35

31.00 6.11

32.00 5.86

33.00 5.62

34.00 5.37

35.00 5.13

36.00 4.89

37.00 4.64

38.00 4.40

39.00 4.15

40.00 3.91

41.00 3.66

42.00 3.42

43.00 3.18

44.00 2.93

45.00 2.69

46.00 2.44

47.00 2.20

48.00 1.95

49.00 1.71

50.00 1.47

51.00 1.22

52.00 0.98

53.00 0.73

54.00 0.49

55.00 0.24

56.00 0.00

Rational Analysis: Rational Method Analysis, 100YR Notes:

Rational Method Input Parameters Runoff Coefficient: 0.20 Basin Area: 30.0000 acres Rainfall Intensity: 1.49 in/hr Time of Concentration: 28.63 minutes Recurrence Year: 100 year

Rational Method Results Flowrate: 9.0 cfs

IDF Input Parameters NOAA Atlas Data State: Oregon Region: Region 4 2 yr, 6 hr: 0.7000 in 2 yr, 24 hr: 1.4000 in 100 yr, 6 hr: 1.5900 in 100 yr, 24 hr: 2.8100 in

IDF Results 100 year IDF equation: i = 25.2415 / (Tc + 9.13962)^0.779343 Intensity: 1.4894 in/hr

Time of Concentration Input Parameters Computed Time of Concentration Time of Concentration: 28.63 min

Sheet Flow Input Parameters Top Elevation: 4991.00 ft Bottom Elevation: 4980.00 ft Length: 150.00 ft Recommended length not to exceed 30 m. Maximum length is 90 m Manning's n: 0.4000 See HDS-2 Table 2.1 2 yr, 24 hr precip: 1.4000 in

Sheet Flow Results Slope: 0.0733 ft/ft Time of Concentration: 26.70 min

Shallow Concentrated Flow Input Parameters Top Elevation: 4980.00 ft

Rational Analysis: Rational Method Analysis, 100YRRational Analysis: Rational Method Analysis, 100YR

Flowrate: 9.0 cfs

Basin 7 has the largest drainage area at 29 acres. For the conveyance capacity analysis, all basins are assumed to be 30 acres.

Bottom Elevation: 4280.00 ft Length: 1540.00 ft k: 0.6000 See HDS-2 Table 2.2

Shallow Concentrated Flow Results Slope: 0.4545 ft/ft Velocity: 13.3492 ft/s HDS-2 equation 2.7 Time of Concentration: 1.92 min

Total Time of Concentration Time of Concentration: 28.63 min

Hydrograph - Rational - Rational Hydrograph Method 100 year recurrence Interval, Peak Discharge: 5.681 cfs, Time to Peak: 28.00 (min), Total Volume:

9443.09 ft^3

Time (minutes) Flow cfs

0.00 0.00

1.00 0.20

2.00 0.40

3.00 0.60

4.00 0.79

5.00 0.99

6.00 1.19

7.00 1.39

8.00 1.59

9.00 1.79

10.00 1.98

11.00 2.18

12.00 2.38

13.00 2.58

14.00 2.78

15.00 2.98

16.00 3.18

17.00 3.37

18.00 3.57

19.00 3.77

20.00 3.97

21.00 4.17

22.00 4.37

23.00 4.56

24.00 4.76

25.00 4.96

26.00 5.16

27.00 5.36

28.00 5.68

29.00 5.48

30.00 5.28

31.00 5.07

32.00 4.87

33.00 4.67

34.00 4.46

35.00 4.26

36.00 4.06

37.00 3.85

38.00 3.65

39.00 3.45

40.00 3.25

41.00 3.04

42.00 2.84

43.00 2.64

44.00 2.43

45.00 2.23

46.00 2.03

47.00 1.83

48.00 1.62

49.00 1.42

50.00 1.22

51.00 1.01

52.00 0.81

53.00 0.61

54.00 0.41

55.00 0.20

56.00 0.00

Channel Analysis: Channel Analysis: 24" Culvert

Input Parameters Channel Type: Circular Pipe Diameter: 2.0000 ft Longitudinal Slope: 0.0100 ft/ft Manning's n: 0.0240 Depth: 2.0000 ft

Result Parameters Flow: 12.2538 cfs Area of Flow: 3.1416 ft^2 Wetted Perimeter: 6.2832 ft Hydraulic Radius: 0.5000 ft Average Velocity: 3.9005 ft/s Top Width: 0.0000 ft Froude Number: 0.0000 Critical Depth: 1.2578 ft Critical Velocity: 5.8894 ft/s Critical Slope: 0.0192 ft/ft Critical Top Width: 1.93 ft Calculated Max Shear Stress: 1.2480 lb/ft^2 Calculated Avg Shear Stress: 0.3120 lb/ft^2 y yChannel Analysis: Channel Analysis: 24" Culvert pDepth: 2.0000 ft

Flow: 12.2538 cfs

Channel Analysis: Channel Analysis: Ditch

Input Parameters Channel Type: Triangular Side Slope 1 (Z1): 1.0000 ft/ft Side Slope 2 (Z2): 1.0000 ft/ft Longitudinal Slope: 0.4000 ft/ft Manning's n: 0.0300 Flow: 9.0000 cfs

Result Parameters Depth: 0.8124 ft Area of Flow: 0.6599 ft^2 Wetted Perimeter: 2.2977 ft Hydraulic Radius: 0.2872 ft Average Velocity: 13.6375 ft/s Top Width: 1.6247 ft Froude Number: 3.7709 Critical Depth: 1.3814 ft Critical Velocity: 4.7161 ft/s Critical Slope: 0.0236 ft/ft Critical Top Width: 2.76 ft Calculated Max Shear Stress: 20.2768 lb/ft^2 Calculated Avg Shear Stress: 7.1689 lb/ft^2 y yChannel Analysis: Channel Analysis: Ditch

Flow: 9.0000 cfs pDepth: 0.8124 ft

Riprap Analysis: Riprap Analysis

Input Parameters Riprap Type: Culvert Outlet Protection Flow: 5.7 cfs Culvert Diameter: 2 ft Normal Depth in Culvert: 0.05934 ft Tailwater Depth: 0.8 ft If tailwater is unknown, use 0.4D flow is supercritical

Result Parameters Tailwater Depth Used in Computations: 0.8 ft Culvert Diameter Used in Computations: 1.02967 ft Computed D50: 2.90416 in

Riprap Class Riprap Name: CLASS I Riprap Class: I The following values are an 'average' of the size fraction range for the selected riprap class.

d100: 12 in d85: 9 in d50: 6.5 in d15: 4.5 in

Layout Recommendations Apron Length: 8 ft Apron Depth: 1.89583 ft Apron Width (at end): 8.42234 ft

Report for channel

Channel Analysis: Channel Analysis Notes:

Input Parameters Channel Type: Trapezoidal Side Slope 1 (Z1): 1.0000 ft/ft Side Slope 2 (Z2): 1.0000 ft/ft Channel Width: 10.0000 ft Longitudinal Slope: 0.4000 ft/ft Manning's n: 0.0150 Flow: 5.7000 cfs

Result Parameters Depth: 0.0593 ft Area of Flow: 0.5969 ft^2 Wetted Perimeter: 10.1678 ft Hydraulic Radius: 0.0587 ft Average Velocity: 9.5489 ft/s Top Width: 10.1187 ft Froude Number: 6.9283 Critical Depth: 0.2146 ft Critical Velocity: 2.6006 ft/s Critical Slope: 0.0056 ft/ft Critical Top Width: 10.43 ft Calculated Max Shear Stress: 1.4811 lb/ft^2 Calculated Avg Shear Stress: 1.4653 lb/ft^2 No channel used in calculations

ODOT Region Map

Water quality design storm factor = 50%

Per ODOT

For cumulative rainfall from the 2-year, 24-hour storm for the project site, the Water Quality Design Storm is 50 percent

For ODOT purposes, minimum storm size (0.7 inches during 24 hours) was selected to make sure that the “first flush” of high pollutant concentration is always captured

Appendix B: CIA Maps

Appendix C: Soils

Figure 3: NRCS Soils Map (Hydrologic Soils Groups)

United States Department of Agriculture

A product of the National Cooperative Soil Survey, a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local participants

Custom Soil Resource Report for Klamath County, Oregon, Southern Part

Natural Resources Conservation Service

June 7, 2017

Preface Soil surveys contain information that affects land use planning in survey areas.

They highlight soil limitations that affect various land uses and provide information about the properties of the soils in the survey areas. Soil surveys are designed for many different users, including farmers, ranchers, foresters, agronomists, urban planners, community officials, engineers, developers, builders, and home buyers.

Also, conservationists, teachers, students, and specialists in recreation, waste disposal, and pollution control can use the surveys to help them understand, protect, or enhance the environment.

Various land use regulations of Federal, State, and local governments may impose special restrictions on land use or land treatment. Soil surveys identify soil properties that are used in making various land use or land treatment decisions.

The information is intended to help the land users identify and reduce the effects of soil limitations on various land uses. The landowner or user is responsible for identifying and complying with existing laws and regulations.

Although soil survey information can be used for general farm, local, and wider area planning, onsite investigation is needed to supplement this information in some cases. Examples include soil quality assessments (http://www.nrcs.usda.gov/wps/ portal/nrcs/main/soils/health/) and certain conservation and engineering applications. For more detailed information, contact your local USDA Service Center (https://offices.sc.egov.usda.gov/locator/app?agency=nrcs) or your NRCS State Soil Scientist (http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/contactus/?

cid=nrcs142p2_053951).

Great differences in soil properties can occur within short distances. Some soils are seasonally wet or subject to flooding. Some are too unstable to be used as a foundation for buildings or roads. Clayey or wet soils are poorly suited to use as septic tank absorption fields. A high water table makes a soil poorly suited to basements or underground installations.

The National Cooperative Soil Survey is a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local agencies. The Natural Resources Conservation Service (NRCS) has leadership for the Federal part of the National Cooperative Soil Survey.

Information about soils is updated periodically. Updated information is available through the NRCS Web Soil Survey, the site for official soil survey information.

The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or a part of an individual's income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require http://www.nrcs.usda.gov/wps/portal/nrcs/main/soils/health/ http://www.nrcs.usda.gov/wps/portal/nrcs/main/soils/health/ https://offices.sc.egov.usda.gov/locator/app?agency=nrcs http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/contactus/?cid=nrcs142p2_053951 http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/contactus/?cid=nrcs142p2_053951 alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410 or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and employer.

Contents Preface How Soil Surveys Are Made Soil Map

Soil Map Legend Map Unit Legend Map Unit Descriptions

Klamath County, Oregon, Southern Part 1—Algoma silt loam, MLRA 21 18B—Dodes loam, 2 to 15 percent slopes 24E—Harriman-Lorella complex, 5 to 35 percent south slopes 30—Histosols, ponded 46—Lather muck 50E—Lorella very stony loam, 2 to 35 percent south slopes 78—Tulana silt loam 81E—Woodcock association, north 82E—Woodcock association, south 83F—Woodcock-Rock outcrop complex, 40 to 60 percent north slopes W—Water

Soil Information for All Uses Soil Reports

Soil Physical Properties Engineering Properties Physical Soil Properties (Saturated hydraulic conductivity )

Soil Qualities and Features Soil Features (Corrosion Potential)

References

How Soil Surveys Are Made Soil surveys are made to provide information about the soils and miscellaneous areas in a specific area. They include a description of the soils and miscellaneous areas and their location on the landscape and tables that show soil properties and limitations affecting various uses. Soil scientists observed the steepness, length, and shape of the slopes; the general pattern of drainage; the kinds of crops and native plants; and the kinds of bedrock. They observed and described many soil profiles. A soil profile is the sequence of natural layers, or horizons, in a soil. The profile extends from the surface down into the unconsolidated material in which the soil formed or from the surface down to bedrock. The unconsolidated material is devoid of roots and other living organisms and has not been changed by other biological activity.

Currently, soils are mapped according to the boundaries of major land resource areas (MLRAs). MLRAs are geographically associated land resource units that share common characteristics related to physiography, geology, climate, water resources, soils, biological resources, and land uses (USDA, 2006). Soil survey areas typically consist of parts of one or more MLRA.

The soils and miscellaneous areas in a survey area occur in an orderly pattern that is related to the geology, landforms, relief, climate, and natural vegetation of the area. Each kind of soil and miscellaneous area is associated with a particular kind of landform or with a segment of the landform. By observing the soils and miscellaneous areas in the survey area and relating their position to specific segments of the landform, a soil scientist develops a concept, or model, of how they were formed. Thus, during mapping, this model enables the soil scientist to predict with a considerable degree of accuracy the kind of soil or miscellaneous area at a specific location on the landscape.

Commonly, individual soils on the landscape merge into one another as their characteristics gradually change. To construct an accurate soil map, however, soil scientists must determine the boundaries between the soils. They can observe only a limited number of soil profiles. Nevertheless, these observations, supplemented by an understanding of the soil-vegetation-landscape relationship, are sufficient to verify predictions of the kinds of soil in an area and to determine the boundaries.

Soil scientists recorded the characteristics of the soil profiles that they studied. They noted soil color, texture, size and shape of soil aggregates, kind and amount of rock fragments, distribution of plant roots, reaction, and other features that enable them to identify soils. After describing the soils in the survey area and determining their properties, the soil scientists assigned the soils to taxonomic classes (units).

Taxonomic classes are concepts. Each taxonomic class has a set of soil characteristics with precisely defined limits. The classes are used as a basis for comparison to classify soils systematically. Soil taxonomy, the system of taxonomic classification used in the United States, is based mainly on the kind and character of soil properties and the arrangement of horizons within the profile. After the soil scientists classified and named the soils in the survey area, they compared the individual soils with similar soils in the same taxonomic class in other areas so that they could confirm data and assemble additional data based on experience and research.

The objective of soil mapping is not to delineate pure map unit components; the objective is to separate the landscape into landforms or landform segments that have similar use and management requirements. Each map unit is defined by a unique combination of soil components and/or miscellaneous areas in predictable proportions. Some components may be highly contrasting to the other components of the map unit. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The delineation of such landforms and landform segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, onsite investigation is needed to define and locate the soils and miscellaneous areas.

Soil scientists make many field observations in the process of producing a soil map.

The frequency of observation is dependent upon several factors, including scale of mapping, intensity of mapping, design of map units, complexity of the landscape, and experience of the soil scientist. Observations are made to test and refine the soil-landscape model and predictions and to verify the classification of the soils at specific locations. Once the soil-landscape model is refined, a significantly smaller number of measurements of individual soil properties are made and recorded.

These measurements may include field measurements, such as those for color, depth to bedrock, and texture, and laboratory measurements, such as those for content of sand, silt, clay, salt, and other components. Properties of each soil typically vary from one point to another across the landscape.

Observations for map unit components are aggregated to develop ranges of characteristics for the components. The aggregated values are presented. Direct measurements do not exist for every property presented for every map unit component. Values for some properties are estimated from combinations of other properties.

While a soil survey is in progress, samples of some of the soils in the area generally are collected for laboratory analyses and for engineering tests. Soil scientists interpret the data from these analyses and tests as well as the field-observed characteristics and the soil properties to determine the expected behavior of the soils under different uses. Interpretations for all of the soils are field tested through observation of the soils in different uses and under different levels of management.

Some interpretations are modified to fit local conditions, and some new interpretations are developed to meet local needs. Data are assembled from other sources, such as research information, production records, and field experience of specialists. For example, data on crop yields under defined levels of management are assembled from farm records and from field or plot experiments on the same kinds of soil.

Predictions about soil behavior are based not only on soil properties but also on such variables as climate and biological activity. Soil conditions are predictable over long periods of time, but they are not predictable from year to year. For example, soil scientists can predict with a fairly high degree of accuracy that a given soil will have a high water table within certain depths in most years, but they cannot predict that a high water table will always be at a specific level in the soil on a specific date.

After soil scientists located and identified the significant natural bodies of soil in the survey area, they drew the boundaries of these bodies on aerial photographs and

Custom Soil Resource Report identified each as a specific map unit. Aerial photographs show trees, buildings, fields, roads, and rivers, all of which help in locating boundaries accurately.

Soil Map The soil map section includes the soil map for the defined area of interest, a list of soil map units on the map and extent of each map unit, and cartographic symbols displayed on the map. Also presented are various metadata about data used to produce the map, and a description of each soil map unit.

Soil Map

0586000 587000 588000 589000 590000 591000 592000 593000

586000 587000 588000 589000 590000 591000 592000 593000 594000

42° 20' 20'' N

1°

7'

0' ' W

42° 20' 20'' N

1°

1'

7'

' W

42° 14' 32'' N

1°

7'

0'

' W

42° 14' 32'' N

1°

1'

7'

' W

N

Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 10N WGS84 0 2500 5000 10000 15000

Feet 0 500 1000 2000 3000

Meters Map Scale: 1:52,200 if printed on A portrait (8.5" x 11") sheet.

MAP LEGEND MAP INFORMATION

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

Soils Soil Map Unit Polygons

Soil Map Unit Lines

Soil Map Unit Points

Special Point Features Blowout

Borrow Pit

Clay Spot

Closed Depression

Gravel Pit

Gravelly Spot

Landfill

Lava Flow

Marsh or swamp

Mine or Quarry

Miscellaneous Water

Perennial Water

Rock Outcrop

Saline Spot

Sandy Spot

Severely Eroded Spot

Sinkhole

Slide or Slip

Sodic Spot

Spoil Area

Stony Spot

Very Stony Spot

Wet Spot

Other

Special Line Features

Water Features Streams and Canals

Transportation Rails

Interstate Highways

US Routes

Major Roads

Local Roads

Background Aerial Photography

The soil surveys that comprise your AOI were mapped at 1:20,000.

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

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

Coordinate System: Web Mercator (EPSG:3857)

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

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

Soil Survey Area: Klamath County, Oregon, Southern Part Survey Area Data: Version 13, Sep 16, 2016

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

Date(s) aerial images were photographed: Jun 30, 2010—Jul 12, 2010

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

Map Unit Legend

Klamath County, Oregon, Southern Part (OR640)

Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI

1 Algoma silt loam, MLRA 21 34.1 4.8%

18B Dodes loam, 2 to 15 percent slopes

1.0 0.1%

24E Harriman-Lorella complex, 5 to 35 percent south slopes

1.0 0.1%

30 Histosols, ponded 2.8 0.4%

46 Lather muck 61.5 8.7%

50E Lorella very stony loam, 2 to 35 percent south slopes

102.0 14.4%

78 Tulana silt loam 3.7 0.5%

81E Woodcock association, north 19.6 2.8%

82E Woodcock association, south 196.4 27.7%

83F Woodcock-Rock outcrop complex, 40 to 60 percent north slopes

163.7 23.1%

W Water 123.9 17.5%

Totals for Area of Interest 709.7 100.0%

Map Unit Descriptions The map units delineated on the detailed soil maps in a soil survey represent the soils or miscellaneous areas in the survey area. The map unit descriptions, along with the maps, can be used to determine the composition and properties of a unit.

A map unit delineation on a soil map represents an area dominated by one or more major kinds of soil or miscellaneous areas. A map unit is identified and named according to the taxonomic classification of the dominant soils. Within a taxonomic class there are precisely defined limits for the properties of the soils. On the landscape, however, the soils are natural phenomena, and they have the characteristic variability of all natural phenomena. Thus, the range of some observed properties may extend beyond the limits defined for a taxonomic class.

Areas of soils of a single taxonomic class rarely, if ever, can be mapped without including areas of other taxonomic classes. Consequently, every map unit is made up of the soils or miscellaneous areas for which it is named and some minor components that belong to taxonomic classes other than those of the major soils.

Most minor soils have properties similar to those of the dominant soil or soils in the map unit, and thus they do not affect use and management. These are called noncontrasting, or similar, components. They may or may not be mentioned in a particular map unit description. Other minor components, however, have properties and behavioral characteristics divergent enough to affect use or to require different management. These are called contrasting, or dissimilar, components. They generally are in small areas and could not be mapped separately because of the scale used. Some small areas of strongly contrasting soils or miscellaneous areas are identified by a special symbol on the maps. If included in the database for a given area, the contrasting minor components are identified in the map unit descriptions along with some characteristics of each. A few areas of minor components may not have been observed, and consequently they are not mentioned in the descriptions, especially where the pattern was so complex that it was impractical to make enough observations to identify all the soils and miscellaneous areas on the landscape.

The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The objective of mapping is not to delineate pure taxonomic classes but rather to separate the landscape into landforms or landform segments that have similar use and management requirements. The delineation of such segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, however, onsite investigation is needed to define and locate the soils and miscellaneous areas.

An identifying symbol precedes the map unit name in the map unit descriptions.

Each description includes general facts about the unit and gives important soil properties and qualities.

Soils that have profiles that are almost alike make up a soil series. Except for differences in texture of the surface layer, all the soils of a series have major horizons that are similar in composition, thickness, and arrangement.

Soils of one series can differ in texture of the surface layer, slope, stoniness, salinity, degree of erosion, and other characteristics that affect their use. On the basis of such differences, a soil series is divided into soil phases. Most of the areas shown on the detailed soil maps are phases of soil series.