THE NEED FOR AN ADDITIONAL SPILLWAY AT THE SANFORD DAM BOILING SPRING LAKES, NC. Presentation for The Brunswick County Commissioners April 20, 2015

Similar documents
INFLOW DESIGN FLOOD CONTROL SYSTEM PLAN 40 C.F.R. PART PLANT YATES ASH POND 2 (AP-2) GEORGIA POWER COMPANY

Emergency Action Plan (EAP) Tata Pond Dam

North Carolina Simplified Inundation Maps For Emergency Action Plans December 2010; revised September 2014; revised April 2015

BRUNSWICK COUNTY. North Carolina State Highway Patrol Coastal Evacuation Plan 1

President s Day Weekend Storm Community Meeting and Workshop April 17, 2017

Probable Maximum Precipitation Study

FRED BURR DAM FEASIBILITY STUDY

Standards for Soil Erosion and Sediment Control in New Jersey May 2012

ATLANTIC INTRACOASTAL WATERWAY NORFOLK DISTRICT. Joel F. Scussel, Operations Support Section Dismal Swamp Canal July 27, 2017

WHAT SEISMIC HAZARD INFORMATION THE DAM ENGINEERS NEED FROM SEISMOLOGISTS AND GEOLOGISTS?

Limited Visual Dam Safety Inspections OA Oahu Reservoir No Oahu, Hawaii

9. PROBABLE MAXIMUM PRECIPITATION AND PROBABLE MAXIMUM FLOOD

FORECAST-BASED OPERATIONS AT FOLSOM DAM AND LAKE

11/21/2014. Erosion and Sedimentation Control Planning and Design Workshop December 2, 2014

HISTORY OF CONSTRUCTION FOR EXISTING CCR SURFACE IMPOUNDMENT PLANT GASTON ASH POND 40 CFR (c)(1)(i) (xii)

Flooding Performance Indicator Summary. Performance indicator: Flooding impacts on riparian property for Lake Ontario and the Upper St.

Suwannee Satilla Basins Flood Control Issues, Opportunities and Assistance

Sediment Trap. A temporary runoff containment area, which promotes sedimentation prior to discharge of the runoff through a stabilized spillway.

New Jersey Department of Transportation Extreme Weather Asset Management Pilot Study

STEUBEN COUNTY, NEW YORK. Hazard Analysis Report

Pompton Lakes Dam Downstream Effects of the Floodgate Facility. Joseph Ruggeri Brian Cahill Michael Mak Andy Bonner

Appendix E Guidance for Shallow Flooding Analyses and Mapping

PRELIMINARY CULVERT ANALYSIS REPORT FOR CULVERT NO. 008-C OREGON AVENUE OVER PINEHURST CREEK

HAZUS-MH: Earthquake Event Report

WEST CATARACT CREEK DAM FINAL DESIGN REPORT

Interpretive Map Series 24

CASE STUDY BINGA, PHILIPPINES

ENGINEERING HYDROLOGY

Section 4: Model Development and Application

CCR Rule Annual Inspection Report (cont.) 2

Route 88 Effects on the Town of Westport. Life time observations. By: Claude A. Ledoux

SEVERE WEATHER 101. Flood Basics

CASE STUDY BINGA, PHILIPPINES

Study 16.5 Probable Maximum Flood (PMF)

US Army Corps of Engineers BUILDING STRONG

Louisiana s NIKE Approach to EAPs: Just Do It

PENNSYLVANIA DEPARTMENT OF TRANSPORTATION ENGINEERING DISTRICT 3-0

Sediment Trap. At multiple locations within the project site where sediment control is needed.

Heavy Rain and Potential for Dangerous Flooding for northeast SC and southeast NC

Miami-Dade County Overview

Rucker Pond. Background

5.2. IDENTIFICATION OF NATURAL HAZARDS OF CONCERN

Between 6 am to 4 pm the next day approximately 7.5 inches fell. Chesapeake Bay Bridge Tunnel NOAA Tide Gage

Community Discovery Data Questionnaire

Folsom Dam Water Control Manual Update

THE TRINITY RIVER VISION/ GATEWAY PARK / PANTHER ISLAND

KENTUCKY HAZARD MITIGATION PLAN RISK ASSESSMENT

Storm Surge Analysis Update Meeting Cross City, Florida June 17, 2014

COMMUNITY EMERGENCY RESPONSE TEAM FLOODS INTRODUCTION

THE TRINITY RIVER VISION/ GATEWAY PARK / PANTHER ISLAND Flood Control Project Update

Bank Erosion and Morphology of the Kaskaskia River

Results of the Sava River Model

Hurricanes. Cause: a low pressure storm system over warm ocean water. Effect: potential massive widespread destruction and flooding.

Attachment B to Technical Memorandum No.2. Operations Plan of Ross Valley Detention Basins

Local Flood Hazards. Click here for Real-time River Information

Rock & Aggregate Drop Inlet Protection

VIRGINIA ELECTRIC AND POWER COMPANY CHESTERFIELD POWER STATION LOWER ASH POND CHESTERFIELD COUNTY, VIRGINIA

UPPER COSUMNES RIVER FLOOD MAPPING

FHWA - HIGHWAY HYDROLOGY

ARTICLE 5 (PART 2) DETENTION VOLUME EXAMPLE PROBLEMS

Hurricane Preparation and Recovery. October 11, 2011 Jon Nance, Chief Engineer, NCDOT

Modeling Great Britain s Flood Defenses. Flood Defense in Great Britain. By Dr. Yizhong Qu

Delaware River Flood Advisory Committee

Hurricane KATRINA Lessons Learned for Managing Risk

Operational water balance model for Siilinjärvi mine

APPENDIX B HYDROLOGY

Study 16.5 Probable Maximum Flood (PMF)

INTRODUCTION TO HEC-HMS

Phases of Disaster Response. John Yeaw, Gavin Vanstone, Haochen Wu, Jordan Tyler

Baldwin County, Alabama

LOCATED IN INDIAN RIVER COUNTY PREPARED FOR S.J.R.W.M.D. AND F.W.C.D. DECEMBER, 2003 Updated 2007 Updated May 2014 PREPARED BY

LOMR SUBMITTAL LOWER NEHALEM RIVER TILLAMOOK COUNTY, OREGON

Response Case Study: April 2014 Historic Flood Event. Severe Weather April 29 30, 2014

Flood Scenario Worksheet

STRUCTURAL STABILITY ASSESSMENT

USING GIS TO MODEL AND ANALYZE HISTORICAL FLOODING OF THE GUADALUPE RIVER NEAR NEW BRAUNFELS, TEXAS

Ground Water Protection Council 2017 Annual Forum Boston, Massachusetts. Ben Binder (303)

Stage Discharge Tabulation for Only Orifice Flow

Application #: TEXT

Managing an Extreme Weather Event of Prolonged Duration May 22, 2013

Summary of Hydraulic and Sediment-transport. Analysis of Residual Sediment: Alternatives for the San Clemente Dam Removal/Retrofit Project,

Issue 44: Phase II & III H&H Issues Date: 07/03/2006 Page 1

Natural and Human Influences on Flood Zones in Wake County. Georgia Ditmore

NC Emergency Management A View from the Counties

Floodplain Mapping & Flood Warning Applications in North Carolina

WATER MANAGEMENT REPORT FOR PAGE ESTATES

PW 001 SNOW REMOVAL AND SANDING FOR ROADWAYS AND SIDEWALKS October 6, 2014 (#223-14) Original October 19, 2015; October 15, 2018 Public Works

Discovery Data Questionnaire

Phillips Ditch Drainage Study

Coastal Flood Risk Study Project for Northeast Florida Study Area

Appendix C. Pleasure Lake Emergency Action Plan


Better estimation of Flood Wave Propagation Time in Meandering Reaches by using 2D-modelling

City of Madison Flooding Event AUGUST 20 TH, 2018-PRESENT

Draft for Discussion 11/11/2016

Weather Information for Surface Transportation (WIST): Update on Weather Impacts and WIST Progress

A Simple Procedure for Estimating Loss of Life from Dam Failure. Wayne J. Graham, P.E. 1

Red River Levee Panel

Chapter 7 Mudflow Analysis

Assumption Parish Hazard Mitigation Plan Update Public Meeting. September 1, 2015 Napoleonville, LA

Transcription:

THE NEED FOR AN ADDITIONAL SPILLWAY AT THE SANFORD DAM BOILING SPRING LAKES, NC Presentation for The Brunswick County Commissioners April 20, 2015

The Sanford Dam Earth Dam constructed in 1961 Drainage area of 6,381 acres (10 sq. miles) Length of 1584 feet Structural height of 30 feet Impounds 285 acres of water Maximum storage of 3,600 acre-feet Designated as a medium size dam Classified as High Hazard

What is a High Hazard dam? Class C (High Hazard) includes dams located where failure will likely cause loss of life or serious damage to homes, industrial and commercial buildings, important public utilities, primary highways, or major railroads.

Dam Hazards Classification Hazard Classification Description Quantitative Guidelines Low Intermediate Interruption of road service, low volume roads Less than 25 vehicles per day Economic damage Less than $30,000 Damage to highways, Interruption of service 25 to less than 250 vehicles per day Economic damage $30,000 to less than $200,000 Loss of human life* Probable loss of 1 or more human lives Economic damage More than $200,000 High *Probable loss of human life due to breached roadway or bridge on or below the dam. 250 or more vehicles per day

Statistics from NC Dam Safety Emergency Action Planning (EAP) Website Most dam failure fatalities are not the result of large dams. Most fatalities are the result of small dam failures. Dam failures resulting in fatalities: 86% of the fatalities have resulted from dams between 20 and 49 feet in height 47% of the fatalities have resulted from dams with a drainage area less than 2 square miles 75 % of the fatalities have resulted from dams with a drainage area less than 10 square miles 7 dams had less than 300 acre-feet of reservoir storage area This description fits many of North Carolina's dams

What our dam looks like today Crest elevation 39.0 ft.

Some definitions A 100-year flood a flood event that has a 1% probability of occurring in any given year. Probable Maximum Precipitation (PMP) "...the theoretical maximum precipitation for a given duration under modern meteorological conditions." The theoretically greatest depth of precipitation for a given duration that is physically possible over a particular drainage area at a certain time of year

NORTH CAROLINA DAM SAFETY LAWS AND REGULATIONS

Three main concerns 1. Worst case scenario The Dam is overtopped at elevation 39.0 ft. and we lose the impoundment with potential loss of life and property. 2. Excessive flooding We cannot keep pace with the watershed and flooding damages roads, property, and eliminates Route 87 as an evacuation route for communities south of BSL. 3. Creation of sink holes Current use of the gates to adjust lake levels in advance of storms helps to create or accelerate the formation of sink holes. The new spillway will maintain consistent levels during storms, without manual operation. No need to depress water by 2 feet!

What could happen after overtopping

Evacuation Routes 87, 211 and 133 Users: Oak Island Caswell Beach Southport St. James Boiling Spring Lakes Military Ocean Terminal Sunny Point Brunswick Nuclear Plant/ Duke Energy

Route 87 Our hurricane evacuation route! 2005, Tropical Storm Tammy 2005, Hurricane Ophelia 1999, Hurricane Floyd 1998, Hurricane Bonnie 1996, Hurricane Bertha 1996, Hurricane Fran Road Elevation 34.4 ft

Other key roads flood at this location Isolate Residents Prevent Emergency Services Response EMS facility is located on north side of Rt. 87 Examples: Boiling Spring Rd (SR1539) Fairway Dr. South Shore Dr. Elm Rd

Sinkholes have drained the lake

Impact on our community

How do we operate our existing gates? Existing gates in the outlet structure are manually operated to maintain consistent lake levels (not recommended). Repeated manual operation creates future risk of gate failures. Drain down rates limited to 1 ft./day by NC Dam Safety, to prevent slope impacts along the lake edge. Safety issue - equipment cannot be operated during rainfall due to lightning shock hazard. So we predict when to lower levels. New spillway open top will enable consistent water levels without manual operation! Outlet Control

New Spillway Top of Dam Existing Spillway Discharge Pipes

Four (4) new discharge pipes of 60 Diameter

Endorsements Wilmington District, US Army Corps of Engineers There is real potential for the dam to be overtopped for storms just above the 100-year event threatening the integrity of the dam Progress Energy Brunswick Nuclear Plant We support and endorse Boiling Spring Lake s effort to increase Sanford Dam s spillway capacity, which is necessary to eliminate the blockage of Highway 87 Brunswick County Department of Energy Management Brunswick County Commissioners (in 2008)

What have we spent in the past? Prior Work Year Approximate Expenditures Install a grout curtain, recoat the inside of original 54" pipes, install pipe couplings, gate modifications and install subdrains Re-lining the original pipes with 40" inserts and grouting void spaces between 1978 $100,000 (estimated) 1989 $92,000 Adding pipe extensions, grouting, and toe drain installation 1991 $75,000 Reconstruction of the downstream face of the dam at the spillway 2001 $124,000 Install four (4) new hydrogates replaced at the existing spillway 2007 $110,000 Engineering Design services for the new Spillway 2013 $130,000 Approximate Total of These Efforts $630,000

Funding This Critical Project Partnership % Participation Estimated Contributions Boiling Spring Lakes 25% $500,000 (dedicated already) Brunswick County 25% - 50% $500,000 - $1,000,000 State of North Carolina?? Federal Agencies?? Estimated Project Cost (2013) $2,200,000

How do we proceed with funding? Spillway Project Schedule First year of project schedule in months Second year of project schedule in months Tasks 1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th 11th 12th 1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th 11th 12th Final Design Review by NC Dam Safety ***** FEMA's CLOMR/LOMR Process ***************************** Advertisement for Construction Bids ****** Pre-Bid Meeting with Contractors ** Bid Review Period *** Contract Award and Notice to Proceed ** Construction Period *********approx. 10 months *********

Please partner with us!