A7 - Philpott Anchors Specs_19 November.pdf

Philpott Dam Anchors and Instrumentation

PART 1 GENERAL

1.1 WORK COVERED BY CONTRACT DOCUMENTS

1.1.1 Project Description

The work includes installation of spillway anchors and automated anchor load sensors.

Also included are installation of inclinometers in monoliths 9 and 13 and automation of crack gauges and piezometers, and incidental related work.

1.1.2 Location

The work is located at the Philpott Lake Dam in Henry and Franklin Counties, Virginia which is approximately 7 miles north of Bassett, Virginia, as indicated on the drawings.

1.2 OCCUPANCY OF PREMISES

Dam will remain operational during performance of work under this Contract.

Before work is started, arrange with the Contracting Officer a sequence of procedure, means of access, space for storage of materials and equipment, and use of approaches, corridors, and stairways.

1.3 EXISTING WORK

Remove or alter existing work in such a manner as to prevent injury or damage to any portions of the existing work which remain.

Repair or replace portions of existing work which have been altered during construction operations to match existing or adjoining work, as approved by the Contracting Officer. At the completion of operations, affected existing work must be in a condition equal to or better than that which existed before new work started.

1.4 LOCATION OF UNDERGROUND UTILITIES

Obtain digging permits prior to start of excavation and comply with installation requirements for locating and marking underground utilities. Contact local utility locating service a minimum of 48 hours prior to excavating, to mark utilities, and within sufficient time required if work occurs on a Monday or after a holiday. Verify existing utility locations indicated on contract drawings, within area of work.

Identify and mark all other utilities not managed and located by the local utility companies.

Scan the construction site with Ground Penetrating Radar (GPR), electromagnetic, or sonic equipment, and mark the surface of the ground or paved surface where existing underground utilities or utilities encased in dam structures are discovered. Verify the elevations of existing piping, utilities, and any type of underground or encased obstruction not indicated, or specified to be removed, that is indicated or discovered during scanning, in locations to be traversed by piping, ducts, and other work to be conducted or installed.

Verify elevations before installing new work closer than nearest manhole or other structure at which an adjustment in grade can be made.

1.4.1 Notification Prior to Excavation

Notify the Contracting Officer at least 48 hours prior to starting excavation work.

1.5 SALVAGE MATERIAL AND EQUIPMENT

Items designated by the Contracting Officer to be salvaged remain the property of the Government. Segregate, itemize, deliver and off-load the salvaged property at a location designated by the Government. Maintain a list of material and equipment to be salvaged, and their storage location. Maintain property control records for material or equipment designated as salvage. Provide a system for property control in the salvage plan. Store and protect salvaged materials and equipment until disposition by the Contracting Officer.

1.6 LAKE OPERATION INFORMATION

Philpott Lake operation information is discussed in the Water Control Plan for Philpott Lake dated June 1992 (minor editorial changes March 2004):

https://epec.saw.usace.army.mil>PhilpottWCP.pdf

In summary, Philpott Dam is operated to maintain the lake level at, or near, the guide curve elevation. The guide curve is at elevation 970.8 feet NAVD88 from October through January and at elevation 972.8 feet

NAVD88 from April through July. The guide curve varies linearly between the two limits from February through March and from August through

September.

The latest information including Project Description, Pertinent Data, Daily Operating Log Files, Daily Reservoir Reports, Projected Lake Levels during Flood Events, Recent Elevation and Flow Information, and Historic Lake Elevation, Inflow and Outflow data are provided on the following website:

https://epec.saw.usace.army.mil/roanphil.htm https://epec.saw.usace.army.mil/roanphil.htm

The hydrograph of the daily mean lake elevation data is provided on

Attachment A.

The Philpott Pool Elevation Duration Curve is provided on Attachment B.

The equipment in the lake may need to be removed if the lake is forecast to rise significantly with an uncontrolled release from the spillway.

The Contractor will need to establish the maximum working lake level for equipment and the necessary lead time to receive notice to evacuate equipment.

Philpott Dam Stability Analysis and Anchors Design 043373

ATTACHMENT A Page 1

ATTACHMENT A – PHILPOTT LAKE HYDROGRAGH

Reservoir Level Hydrograph

USACE Gage Data Website:

h�ps://epec.saw.usace.army.mil/roanphil.htm

USGS Gage Data Website:

h�ps://waterdata.usgs.gov/nwis/inventory?agency_code=USGS&site_no=02071900

1950 1960 1970 1980 1990 2000 2010 2020

E le va ti o n ft

N

A V

D

Year

Philpot Reservoir Stage Hydrograph, ft NAVD88 (Sept 1953 - Sept 2024)

USACE Data USGS Data

Notes:

- Time indicated in USACE and USGS reservoir level records is 2400 , unless otherwise indicated in the specific record.

- USACE data from 9/1/1953 - 12/30/2022.

- USGS data from 12/31/2022 - 9/30/2024.

- Max. WSE recorded from USGS continuous data is 984.71 ft NAVD 88 on 05/22/2020.

Philpott Dam Stability Analysis and Anchors Design 043373

ATTACHMENT B Page 1

ATTACHMENT B – PHILPOTT POOL ELEVATION DURATION CURVE

Updated Figure 4.4 with New Reservoir Level Data

0 10 20 30 40 50 60 70 80 90 100

P h il p o t

R e se rv o ir

L e v e l, F e e t N

A V

D

Percent of Time Philpot Level is Greater Than or Equal to Elevation Shown

Philpot Pool Elevation Duration Curve

Reservoir Level Top of Conservation Pool Top of Flood Control Pool

Note: Duration curve is based upon Period of Record data from Sept 1953 to Sept 2024