lake repair project - boulder county, colorado · -riprap-lined spillway directs flood flows into...

PROJECT ELEMENT DESCRIPTIONS A Lake 4 Northwest Embankment and Emergency Spillway -Breach repair with clay core -Riprap-lined spillway directs flood flows into Lake 4 B Lake 3 Return Channel to South Branch Ditch -Existing channel, no repair needed -Conveys flows from Lake 3 to South Branch if necessary under normal conditions C Lake 4 Inlet Repairs -Embankment repair -Reconstruct run-down from South Branch diversion on re- paired embankment D Lake 4 Sediment Removal Area -Remove large volume of sediment in bottom of Lake 4 E Lake 4 Emergency Spillway -Cut/fill to create emergency spillway -Construct access road and cut-off wall on crest to outlet F Lake 4 Dam /Eastern Embankment -Reconstruct embankment with toe drain G Lake 4 Outlet Structure -Demo/remove existing outlet structure -Install new outlet (two towers with pipeline in between) L-1 Clough & True Ditch Disposal Area (PW 1198) -Place fill material to restore function of ditch L-2 West Lake Fill Area -Place up to 152,000 CY in bottom of reservoir (dead storage) L-3/ WL West Lake Embankment Repair (PW 1196) -Restore dam/embankment with clay core & outlet to A-Frame -Add emergency spillway and siphon for ditches -Reconstruct South Branch light-vehicle crossing (box culvert) L-4/ AF A-Frame Pond Outlet Repair (PW 1196) -Construct outlet, including box culvert to creek -Restore scour area including 61st St. L-5 Ramey Fill Area -Utilize sediment as fill to restore scoured upland area L-6 Fill Exported to County Yard for Future Projects -Haul fill via 61st Street (Haul distance = 4.0 mi.) OP-1 Outlet Pipeline—Relined -Slip line 2,100 LF of existing pipeline (purple dashed line) -Install 4 new manholes for pipeline access (orange dots) OP-2 Outlet Pipeline- — New Segment -300 LF of new pipeline OP-3 Outlet Pipeline—Measurement Structure -In-ground vault with flume measurement (shown orange) -Pipeline discharges into A-Frame Pond outlet near creek OP-4 Outlet Pipeline -Staging and Refueling Areas L-1 B A C D E F G L-4 Lake 2 Lake 3 West Lake Lake 4 A-Frame Pond South Branch Highway 66 Access Exisng Concrete Creek Crossing Construcon Access (61st/63rd St) L-2 L-3 L-5 L-6 OP OP-1 OP OP-4 OP OP-3 OP OP-2 WL WL AF AF Hygiene Rd Access February 2019 Site Plan—Lake Repair Project

Upload: others

Post on 20-Sep-2020

4 views

Category:

Documents

0 download

Report

Download

Embed Size (px):

TRANSCRIPT

Page 1: Lake Repair Project - Boulder County, Colorado · -Riprap-lined spillway directs flood flows into Lake 4 Lake 3 Return hannel to South ranch Ditch-Existing channel, no repair needed-onveys

PROJECT ELEMENT DESCRIPTIONS

ALake 4 Northwest Embankment and Emergency Spillway -Breach repair with clay core-Riprap-lined spillway directs flood flows into Lake 4

Lake 3 Return Channel to South Branch Ditch -Existing channel, no repair needed-Conveys flows from Lake 3 to South Branch if necessary undernormal conditions

Lake 4 Inlet Repairs -Embankment repair-Reconstruct run-down from South Branch diversion on re-paired embankment

DLake 4 Sediment Removal Area -Remove large volume of sediment in bottom of Lake 4

ELake 4 Emergency Spillway -Cut/fill to create emergency spillway-Construct access road and cut-off wall on crest to outlet

FLake 4 Dam /Eastern Embankment -Reconstruct embankment with toe drain

GLake 4 Outlet Structure -Demo/remove existing outlet structure-Install new outlet (two towers with pipeline in between)

L-1Clough & True Ditch Disposal Area (PW 1198) -Place fill material to restore function of ditch

L-2West Lake Fill Area -Place up to 152,000 CY in bottom of reservoir (dead storage)

L-3/

West Lake Embankment Repair (PW 1196) -Restore dam/embankment with clay core & outlet to A-Frame-Add emergency spillway and siphon for ditches-Reconstruct South Branch light-vehicle crossing (box culvert)

L-4/

A-Frame Pond Outlet Repair (PW 1196)-Construct outlet, including box culvert to creek-Restore scour area including 61st St.

L-5Ramey Fill Area -Utilize sediment as fill to restore scoured upland area

L-6Fill Exported to County Yard for Future Projects -Haul fill via 61st Street (Haul distance = 4.0 mi.)

OP-1 Outlet Pipeline—Relined -Slip line 2,100 LF of existing pipeline (purple dashed line)-Install 4 new manholes for pipeline access (orange dots)

OP-2 Outlet Pipeline- — New Segment

-300 LF of new pipeline

OP-3 Outlet Pipeline—Measurement Structure -In-ground vault with flume measurement (shown orange)-Pipeline discharges into A-Frame Pond outlet near creek

OP-4 Outlet Pipeline -Staging and Refueling Areas

LL--11

DD EE

LL--44

Lake 2

Lake 3

West

Lake

Lake 4

A-Frame

PondSo

uth