A07_-_Rosecreek18.pdf

ROSE CREEK DAM

INTRODUCTION

The Rose Creek Dam is located off stream in the Rose Creek canyon. The inspection was conducted on 14 November 2018.

DAM DESCRIPTION AND HISTORY

The dam is an earthfill embankment with riprap covering. The structure is 582 ft in length and 18 feet high and 8.5 to 12 feet wide at the top. The dam enclosed a natural bowl off of Rose Creek Canyon. The dam was design by the United States Bureau of

Reclamation (USBR) in cooperation with the United States Navy (USN). Construction was accomplished by USN Bureau of Yards and Docks. The dam was completed in 1938.

The dam is located at approximately 6300 feet elevation.

INSPECTION PROCEDURES

The field inspection included a complete visual inspection by the Civil Engineer/Dam

Inspector of all components above ground and water level. Camera and tape were used.

INSPECTION RESULTS

Inlet Works

The inlet works consist of diversion structure (upper Rose catch basin) approximately 1 mile upstream from the dam. It is connected to the reservoir by a six inch steel pipe running from the catch basin to the dam and reservoir. The catch basin need to have some patch work done on the concrete structure.

Dam

The dam consists of an earthen embankment of fairly homogenous material that was originally covered with riprap. The interior of the dam has been lined with gunnite or shotcrete.

Outlet Works

The outlet is an 8 in. pipe in the bottom of the dam. At the downstream toe of the embankment the pipe y’s into two 8 in. pipes with left hand valve discharging back to

Rose Creek, and the right hand valve discharging to the depot. Both valves are fully functional and seat tightly. The left hand valve discharges into a concrete box and goes under Rose Creek Road.

Spillway

The spillway is a channel on the south- east corner of the Reservoir. It originally had two concrete abutments 31 feet apart and three feet above existing ground. Downstream of the abutments is a 12 in. corrugated metal pipe (CMP) vertical placed so low water flows can go under the access road. On the outside of the access road is a concrete box which the pipe is connected. This collection box has a 12 in CMP that is connected to another box half way down the hill. The final box is next to the Rose Creek Road.

Inspections

The screen on the inlet works is missing and has been for some time based on the silt in it on the bottom of the catch basin (Figures 1 &2). The valve at the reservoir end is in functioning condition according to Garth Price water operator. (

The dam is covered with willows growing on the face and thru the gunite liner. The trees have been removed from the face of the dam. These are now being replaced by woody shrubs and bushes (Figures 4-6).

The discharge gate vale at the toe of the dam is being used to throttle the water leaving the reservoir. Care should be exercised when doing this that the valve gate does not have a half moon cut into it. Thus preventing discharge from being shut off. The discharge box has rocks and dead weeds in it (Figure 8). The blow down and channel needs to be kept clear of brush and trees (Figure 9)

Brush is growing in the overflow spillway. The culver under Rose Creek road is missing.

Water is an off color of dirty green.

The fence around the reservoir is falling down.

RECOMMENDATIONS

The dam is in good condition overall. Some work needs to be done to help maintain that condition.

Replace and keep in place the screen on the inlet at the catch basin to prevent the inlet piping from becoming plug with leaves and other debris.

Remove willow growing through the liner (Figure 7). Evaluate the liner for large cracks and other damaged areas which could allow water under the liner. The gunite liner on the dam needs to be sounded annually. As hollow spots under the liner are found, they should be filled with neat cement. Ideally this would be placed under pressure to insure that the voids are filled completely. Holes in the liner should be patched.

Since all the trees and brush where removed from the top and downstream face of the dam the brush (willows and woody shrubs) need to be trimmed back on a regular basis.

Establish program to monitor for seepage and leaks around tree stumps Clean access road of curt material and brush road way

The concrete box on the discharge to waste line should be free of debris. Also keep the down stream end of the culvert free of dirt and debris.

The corrugated pipe in the downstream slope needs to be recovered. The outside edge of the reservoir access road needs to be stabilized. And a culvert needs to be installed under

Rose Creek Road to prevent it from washing out.

Repair the fence around the reservoir. Cut brush out of fence (Figures 10 and 11).