23_-_190102__Ash_Meadows_NWR__Inventory_Assessment_Memorandum.pdf

R:\1700\1772\1772.23_2018seedprogam\Ash_Meadows\Documents\Inventory_Assessment_Memo\190102_Ash Meadows NWR Inventory Assessment Memo_F.Docx

January 2, 2019

To: Audrey Coy U.S. Fish & Wildlife Service Headquarters

MS: BMO

5275 Leesburg Pike Falls Church, Virginia 22041-3803

From: Danielle Hannes, P.E. and Andrea Fasen, EI, W. W. Wheeler and Associates, Inc.

No: #1772.23

Re: Dam Inventory Assessment for structures on Ash Meadows National Wildlife Refuge, Nye County, Nevada, Contract No. F15PC00157, Task Order 140F0518F0084.

1.0 INTRODUCTION

This memorandum documents the results of the dam inventory assessment performed at Ash Meadows National Wildlife Refuge (Refuge). The Refuge is located in southwestern Nevada, as shown on Figure No. 1. Several impoundment structures have been identified at the Refuge that were documented to potentially meet the qualifications of an inventory dam in accordance with the U.S. Fish and Wildlife Service (FWS) criteria. These potential impoundment structures were documented in a memorandum prepared by W. W. Wheeler and Associates, Inc. (Wheeler) in the 2005 SEED Inspection Report; the National Dams Inventory (NID); and the State of Nevada’s records. Wheeler also discussed potential impoundment structures with the Refuge Manager and reviewed the LiDAR data to assess if there were impoundments that had not been previously identified.

To document if the impoundment structures meet FWS criteria for inventory dam structures, Wheeler used the LiDAR data to obtain dam heights and estimate reservoir capacities. Wheeler also performed a reconnaissance site visit to each potential inventory structure to collect field measurements during the dates of November 13 – 15, 2018. If the structure was documented to meet the qualifications of an inventory dam, Wheeler also performed a dam inspection during the site visit.

Audrey Coy

2.0 INVENTORY EVALUATION

The potential impoundment structures that were identified and assessed for their inventory status are shown on Figure No. 2 and documented in Table Nos. 1 and 2. To meet inventory dam status in accordance with FWS criteria, the dam must meet one of the following criteria:

(1) It has a storage capacity at maximum water storage elevation in excess of 15 acre-feet, and:

(a) It is higher than 25 feet from the natural bed of the stream (or a watercourse) to the maximum water storage elevation measured at the downstream toe of the dam, or

(b) If it is not across a stream channel or watercourse, it is higher than 25 feet measured from the lowest elevation of the outside limit of the dam to the maximum water storage elevation;

(2) It exceeds an impounding capacity at maximum water storage elevation of 50 acre-feet and a height in excess of 6 feet; or

(3) It has a high or significant hazard classification.

The storage capacity was calculated for each structure using the following equation (USDA, 1980):

Volume (acre-feet) = 0.4 * Height (feet) * Surface Area at Dam Crest (acres)

The surface area for the reservoir associated with each structure was calculated in ArcGIS 10.5 using 1-meter LIDAR data (FWS, 2007) using the contour of the highest continuous contour elevation of the dam crest. The dam heights were documented using the LiDAR data and confirmed during the site visits with field measurements. Table Nos. 1 and 2 summarize the surface areas and calculated storage capacities associated with each structure based on the equation above.

3.0 RECOMMENDATIONS

As a result of Wheeler’s dam inventory assessment at Ash Meadows NWR, Wheeler recommends that Lower Crystal Dam and Horseshoe Dam be classified as Inventory Dams. The other structures that were evaluated, as documented in Table No. 2, are considered to not meet the qualifications of inventory dam structures in accordance with FWS criteria.

It should be noted that a hazard classification evaluation has not been performed on the non-inventory structures identified in Table No. 2, so it was not confirmed if these structures pose a hazard, which could result in them being considered inventory structures. A hazard classification evaluation of Lower Crystal Dam and Horseshoe Dam will be performed as part of this task order.

4.0 REFERENCES

1. U.S. Fish and Wildlife Service, 361 FW2, Dam Safety Program Description, Definitions, and

Standards.

2. U.S. Fish and Wildlife Service (FWS, 2007), 1-meter DEM, flown 2007, provided by

Cartographic Technician from Las Vegas office October 2018.

3. U.S. Department of Agriculture (USDA, 1980), Engineering Field Manual, Chapter 11: Ponds and Reservoirs, April 1980.

ATTACHMENTS

Table 1 - Summary of Documented Impoundments on Refuge – Inventory Dams Table 2 - Summary of Documented Impoundments on Refuge – Non-Inventory Structures

Figure 1 – Vicinity Map Figure 2 – Documented Impoundments Map

Appendix A – Non-Inventory Dams Documentation Appendix A-1 – Upper Horseshoe Site Map and Photos Appendix A-2 – Peterson Site Map and Photos Appendix A-3 – North Structure Site Map and Photos Appendix A-4 – Road 1 Site Map and Photos Appendix A-5 – Dam C Site Map and Photos

Appendix B – Inventory Dams Documentation Appendix B-1 – Lower Crystal Dam Site Map and Photos Appendix B-2 – Horseshoe Dam Site Map and Photos

Table No. 1 – Summary of Documented Impoundments on Refuge Inventory Dams

Structure Name

Latitude/ Longitude Identified In: Comment:

Height (feet)

Surface Area

(acres)

Storage (acre-feet) Status Appendix

Lower Crystal Dam

36.394567 / -116.33103

Wheeler 2005

NID: NV10341 (Lake No. 7) (Nevada inspection reports indicate NV10539, NV10540)

Nevada Inventory:

J-476 (Crystal Marsh Upper Dam), J-477 (Crystal Marsh Lower Dam)

Lower Crystal Dam includes two separate embankments.

Site visit confirmed that this structure meets the qualifications of an inventory dam based on storage and height.

6.1 121 295 Inventory B-1

Horseshoe Dam

36.4028 / -116.3401

NID: NV10340 (Lake No. 6) (Nevada inspection report indicates NV00190), Nevada Inventory: J-093 (Lake No. 6)

Site visit confirmed that this structure meets the qualifications of an inventory dam.

8.7 16 56 A Inventory B-2

A Storage capacity was updated using the contour data generated using LiDAR as part of the SEED Report and Hazard Classification Report.

Updated storage was 77.5 acre-feet at the dam crest.

Table No. 1 – Summary of Documented Impoundments on Refuge Non-Inventory Structures

Structure Name

Latitude/ Longitude Identified In: Comment:

Height (feet)

Surface Area

(acres)

Storage (acre-feet) Status Appendix

Upper Horseshoe

36.4075 / -116.3419 Wheeler 2005

LiDAR data confirmed that this structure does not meet inventory criteria based on storage.

6.3 13.5 34 Non-

Inventory A-1

Peterson Dam

36.447867 / -116.35655

NID: NV10338 (Lake No. 4), NV10339

(Lake No. 5)

Nevada Inventory: J- 091 (Lake No. 4)

Peterson Lake includes separate embankments on the south (Lake No. 4) and the west (Lake No. 5) side of the lake.

Site visit documented that the dam is breached. The Refuge does not plan to make repairs. Wheeler was tasked with developing a breach memorandum to document the required size of the breach in accordance with FWS criteria.

8.9 74 263

Non- Inventory after breach is sized.

A-2

North Structure

36.485483/ -116.33833 Wheeler 2005

This structure was documented in the field to not meet inventory criteria based on height.

3.5 N/A N/A Non-

Inventory A-3

Road 1 36.425333/ -116.36805 Wheeler 2005 Site visit confirmed this is a road crossing with no water control structure. 0 N/A N/A Non- Inventory A-4

Dam C 36.410117/

-116.26113 NID: NV00106

Site visit confirmed that this dam has been purposefully breached. The Refuge continues to enlarge the breach using the embankment materials for roads on the

Refuge. Breach is 450 feet wide.

N/A N/A N/A Non- Inventory A-5

Lake No. 8 36.390000/

-116.29970 NID: NV10342

Site visit, LiDAR, and discussion with the Refuge Manager confirmed that an impoundment does not exist in this location.

N/A N/A N/A N/A N/A

Lake No. 3 36.46970/

-116.3497 NID: NV10337

LiDAR and discussion with the Refuge Manager confirmed that an impoundment does not exist in this location.

N/A N/A N/A N/A N/A

Pahrump

")127 ")160

Las Vegas

ASH MEADOWS NATIONAL

WILDLIFE REFUGE

Lakeview

Nye County

Winnemucca

NEVADA

OREGON IDAHO

UTAH

CALIFORNIA

ARIZONAq

0 6030 Miles

ASH MEADOWS NATIONAL WILDLIFE REFUGE

VICINITY MAP

JANUARY 2019

U.S.

FISH & WILDLIFE

SERVICE

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FIGURE 1

Dam C

Peterson Reservoir

(Lake No. 4 and

Lake No. 5)

Crystal Reservoir (Already Inventory)

Lower Crystal Dam (Lake No. 7, Crystal Marsh Upper Dam/ Lower Dam)

Upper Horseshoe Reservoir

North Structure

Road 1

Horseshoe Reservoir

(Lake No. 6)

Lake No. 8

Lake No. 3 Invite

Road

Bob Rudd Memorial Highway As h M ea do ws

R oa d

Bell Vista Road

Lo ng str ee t S pri ng R oa d

Pe ter so n R es erv oir R oa d

Unknown Road

Point of Rocks Road

Spring Meadows Drive

Spring Meadows Road

Nye County Road

Ash Meadows Road

0 1 20.5 Miles

ASH MEADOWS NATIONAL WILDLIFE REFUGE

DOCUMENTED IMPOUNDMENTS

JANUARY 2019

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FIGURE 2

U.S.

FISH & WILDLIFE

SERVICE

Refuge Headquarters

Legend Documented Impoundments Ash Meadows NWR Headquarters Theoretical Maximum Water Surface Roads Ash Meadows NWR Bounday

APPENDIX A-1

UPPER HORSESHOE

JANUARY 2019

ASH MEADOWS NWR

INVENTORY ASSESSMENT MEMO

UPPER HORSESHOE

JANUARY 2019

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FIGURE A-1

FLOW

0 100 200 Feet

2 FT CONTOUR

ASH MEADOWS NATIONAL WILDLIFE REFUGE

INVENTORY STRUCTURES ASSESSMENT MEMO

UPPER HORSESHOE

A.1-1

1. View looking right and upstream at the crest and downstream slope.

2. View looking down at the top of the three-foot-diameter half-round CMP inlet riser.

Note the wooden stoplogs.

FLOW

FLOW CREST

APPENDIX A-2

PETERSON

(LAKE NO. 4 AND NO. 5)

PETERSON (LAKE NO. 4 AND NO. 5)

JANUARY 2019

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FIGURE A-2

0 1,000

Feet

FLOW

(AT HIGH WSE)

PETERSON LAKE (LAKE NO. 4 AND LAKE NO. 5)

A-2.1

1. (Lake No. 5 Dam) View looking right across the top of the breach from the left side of the breach. Note the tall reeds prevented access; only the top of the water flowing through the breach could be observed (approximately 6.5-feet below the dam crest).

2. (Lake No. 5 Dam) View looking left from the breach at the upstream side of the embankment. Tall reeds were impassible preventing an inspection of the embankment.

FLOW

T.O.

BREACH

REEDS ON

UPSTREAM

EMBANKMENT CREST

A-2.2

3. (Lake No. 5 Dam) View looking left from the breach at the crest of the embankment.

4. (Lake No. 5) View looking left from the breach at the downstream side of the embankment. Note, the large tree on the downstream toe shown in Photo No. 5.

LARGE TREE ON DOWNSTREAM

EMBANKMENT, SEE PHOTO NO. 5

A-2.3

5. View looking left along the west embankment/Lake No. 5 embankment at a large tree approximately 2-feet in diameter on the downstream toe.

6. View looking upstream at erosion rills forming on the crest of Lake No. 5 embankment.

A-2.4

7. (Dam No. 5) View looking at the downstream toe, note the presence of wetland vegetation and saturated conditions downstream of the toe.

8. View looking right from the top of the sand berm between the Lake No. 5 and Lake

No. 4 embankment. Note, only one body of water exists between the two embankments (Peterson Lake). Thick impassible reeds extended between the crest and water surface. Lake No. 4 embankment is not shown but located to the right of the picture.

EMBANKMENT FOR

LAKE NO. 5 DAM

PETERSON LAKE

A-2.5

9. (Dam No. 4) View looking left at one of the low areas approximately 24-feet long and 2-feet below the surrounding crest elevation

10. (Dam No. 4) View looking left across a low area approximately 10-feet-wide. Note the thick, tall vegetation was representative of the upstream and downstream condition thought the embankment.

A-2.6

11. (Dam No. 4) View looking right across a low area about 30-feet-wide and 4-feet below the crest.

12. View looking right at the crest for Lake No. 4 Dam. In the distance is the embankment of Lake No. 5 Dam and the reservoir water surface.

LAKE NO.

4 DAM

LAKE NO.

5 DAM

RESERVOIR

APPENDIX A-3

NORTH STRUCTURE

NORTH STRUCTURE

JANUARY 2019

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FIGURE A-3

0 200

Feet

A-3.1

1. View looking right at downstream slope. Note low area on crest, height relative to downstream toe from low spot location measured in the field as 3.5 feet.

2. View looking left across open channel spillway and downstream slope.

LOW SPOT

ON CREST

SPILLWAY

A-3.2

3. View looking upstream at outlet of uncontrolled culvert. Height from crest to bottom of eroded pool was measured in the field as 5.5 feet.

CULVERT

APPENDIX A-4

ROAD 1

ROAD 1

JANUARY 2019

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FIGURE A-4

0 1,000

Feet

A-4.1

1. View from the right side of the asphalt low flow crossing looking left. Beyond the low flow crossing are three sets of culverts under the dirt road.

2. View looking downstream at the projecting inlet of the two 3-foot-diameter uncontrolled coated CMP’s.

A-4.2

3. View looking downstream at the projecting inlet of the singular 5-foot-diameter uncontrolled CMP culvert.

4. View looking downstream at flared inlets of two 5-foot-diameter uncontrolled, coated

CMP’s.

APPENDIX A-5

DAM C

DAM C

JANUARY 2019

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FIGURE A-5

0 1,000

Feet

Breach bottom width approximately 450-feet-wide (measured using GPS waypoints taken in the field and GIS)

A-5.1

1. View looking upstream from the Refuge access road at the downstream dam embankment and breach.

2. View looking left and upstream at the base of the left side of the breach. Note the stockpiled soil which is from the Refuge who is currently using the remaining embankment as a source of borrow fill for projects on the Refuge.

BREACH

CREST CREST

CREST BORROW

PILES

A-5.2

3. View looking right and upstream at the base of the right side of the breach. Note the excavator which is part of the on-going continued excavation of the breach as borrow material for the Refuge.

CREST AND

DOWNSTREAM

EMBANKMENT TO THE

RIGHT OF THE BREACH

ON-GOING EXCAVATION OF

EMBANKMENT AS SOURCE

OF BORROW MATERIAL

APPENDIX B-1

LOWER CRYSTAL DAM

(LAKE NO. 7, CRYSTAL MARSH

UPPER DAM/LOWER DAM)

Lower Crystal Reservoir (Lake No. 7)

Main Embankment - Right Abutment

Sta. 5+50

Main Embankment - Left Abutment

Sta. 2+60

Emergency Spillway Sta. 0+00

Trapezoidal channel, 10-foot-wide at base

Right Embankment - Left Abutment

Sta. 12+80

Right Embankment Right Abutment

Sta. 32+85

Access to embankment not possible from Sta. 17+65 to 32+85

(excessive grass vegetation)

Combined Service Service Spillway Outlet Works

Sta. 4+40 3-foot-Diameter Half-Round

CMP Intake Riser

Ditch Sta. 18+40

2+003+00

Water Surface at Elevation 2146

Staff Gage Sta. 10+00

7+00

0+00

9+00

4+0

5+00

8+00

6+00

1+00

11+00

24+0023+0022+00

17+00 16+00

15+00 14+00

13+00 12+00

10+00

27+00 28+00

29+00

21+00 20+00

19+00

32+85

25+00

26+00

30+00 31+00

32+00

18+00

ASH MEADOWS NATIONAL WILDLIFE REFUGE

LOWER CRYSTAL DAM

SITE MAP

APRIL 2019

U.S.

FISH & WILDLIFE

SERVICE

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FIGURE B-1

p

0 300 Feet

FLOW

10 FT CONTOUR

B-1.1

1. View looking left from approximate Station 5+50, the Main Embankment right abutment, at the upstream slope (which is mostly obscured and inaccessible due to wetland vegetation) and crest.

2. View looking left from approximate Station 17+65 on the Right Embankment at the dam crest.

CREST UPSTREAM

SLOPE

B-1.2

3. View looking right from approximate Station 17+65 on the Right Embankment at the crest and start of impassible vegetation covering the dam crest, upstream and downstream slopes.

4. View looking right and downstream at the control section and downstream discharge of the emergency spillway channel at Sta. 0+00. The base of the control crest was approximately 10-feet wide.

EMERGENCY

SPILLWAY

CONTROL

CREST

B-1.3

5. View looking upstream at the approach channel to the combined service spillway outlet works at Sta. 4+40.

6. View looking down into the inlet intake of the combined service spillway outlet works, a three-foot-diameter half round CMP riser with stoplogs.

2x4 WING

WALLS

FLOW

STOPLOG

SLOTS

B-1.4

7. View looking downstream at the outflow of the combined service spillway outlet works and downstream discharge channel.

8. View looking left from near Sta. 12+80 at naturally high topographic area between the main embankment and right embankment.

MAIN

EMBANKMENT

APPENDIX B-2

HORSESHOE

(LAKE NO. 6)

Emergency Spillway Sta. 12+65 Trapezoidal channel, approx.

20-ft-wide at base

Combined Service Spillway/Outlet Works Sta. 7+75 4-foot-square riser with stoplog controls, discharges to a 2-foot-diameter CMP

Discharge Structure Sta. 0+20 3-foot-diameter half-round CMP riser with a 2-foot-diameter

CMP

Erosion on downstream side of crest near Sta. 11+50

Typical soft soils at downstream toe of embankment near Sta. 5+40 Rut on crest from Sta. 5+30 to 5+80

Erosion on downstream side of crest near Station 5+00.

Shallow longitudinal cracking on dam crest.

Lower Crystal Reservoir

Horseshoe Reservor (Lake No. 6)

7+00

1+00

3+00

4+00

6+00 9+

+0

13+85

0+00

2+00

5+00

8+0

13+00

+0

12+

ASH MEADOWS NATIONAL WILDLIFE REFUGE

HORSESHOE DAM

SITE MAP

APRIL 2019

U.S.

FISH & WILDLIFE

SERVICE

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FIGURE B-2

p

0 200 Feet

10 FT CONTOUR

HORSESHOE (LAKE NO. 6) DAM

B-2.1

1. View upstream slope looking left from Station 5+40.

2. View upstream slope looking right from Station 5+40.

B-2.2

3. View of the crest looking right from Station 3+00.

4. View of the crest looking left from Station 12+00.

B-2.3

5. View of the downstream slope looking right from Station 9+65.

6. View of the discharge structure at Station 0+20 3-foot-diameter half round inlet riser looking downstream from the approach channel. A height of 6.1 feet was measured from the dam crest to the upstream invert elevation.

B-2.4

7. View of combined service spillway/outlet works approach channel and inlet looking upstream from the crest near Station 7+75. Note the upstream channel is filled with vegetation. The height from the dam crest to the inlet invert was 8.65 feet.

8. View looking downstream at the outlet and downstream embankment for the combined service spillway/outlet structure.

B-2.5

9. View looking right across the emergency spillway control section from the left side of the spillway near Station 12+65.

10. View looking upstream and left from a sand berm downstream and right of the right abutment at the emergency spillway relative to the crest and right abutment.

EMERGENCY

SPILLWAY

DAM CREST