WSP07002

• File Number: 8449
• Description: Platte River Studies
• State: CO
• Basin: South Platte
• Date: 2/1/1991
• Author: City of Greeley
• Title: Feasibility Study for Rehabilitation of Hourglass Dam and Reservoir Vol. 1
• Water Supply Pro - Doc Type: Publication

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rlprap, there were some small bushes and trees beginning to grow. These were not
signiflcanl at the time of our visit. Then! were no evidences of significant erosion damage
on the upstream slope. There were a fIIw small rodent holes along the upper portion of
the slope which did not appear to ailed the Integrity of the structure.

5,2,2.4 Downstream Face

Generally. the downstream face was sparsely covered with grasses. There were no
Indications of cracks, settlements, depressions, or bulges on the downstream face, and there
were no Indicallons of signiflcanl erosion. A dttch and berm have been constructed on the
road across the downstream face to dired: water from the downstream face. The discharge
end of Ihe ditch was beginning to erode back across Ihe downstream face of the dam,
There were a number of smalllrees .rowing on the downslream face. These were generally
about 1 to 4 feet tall, except on the extreme left end of the embankmenl, where there were
a few aspen trees about 15 to 20 feel tall.

5,2,2,5 Seepage

The seepage area between about Stations 114 + 00 and 117 + 00 was dry at the time of our
AuguSI 1990 vlstt. This area was generaDy covered wtth vegetation and deadwood, and did
not show any evidences of erosion from flowing water. Several areas of seepage were
observed extting into the right side of the discharge channel near the energy dissipator and
exlendlng about 60 feet downslream. These flows were clear and no evidence of particle
migration was observed. The majority 01 the flow was confined to an area about 10 feet
by 10 feet, lcealed about 60 feel downslream of the energy dlssipator. This area had been
covered wtth gravel and stones, and the seepage was collected and measured In a V-notch
weir. It Is estimated that 0,5 to 1 gaBon per minute of water was flowing through the V-
notch weir at the time of our vlstt.

5,2,3 OUTLET WORKS

The outlet works were In operation at Ihe lime of our vlstt; therefore, the Intake structure and
condutt could not be observed. Those portions of the energy disslpator which were visible
appeared to be In good condttion, No signiicant delerioration or cracking of the concrete were
noted, However, the lower surfaces of the energy disslpator could not be observed due to

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