HomeMy WebLinkAbout860537.tiff RESOLUTION
RE: APPROVE PLAN OF WORK FOR LONE TREE CREEK FLOOD PLAIN
MANAGEMENT STUDY AND AUTHORIZE CHAIRMAN TO SIGN
WHEREAS, the Board of County Commissioners of Weld County,
Colorado, pursuant to Colorado statute and the Weld County Home
Rule Charter, is vested with the authority of administering the
affairs of Weld County, Colorado, and
WHEREAS, the Board has been presented with a Plan of Work for
the Lone Tree Creek Flood Plain Management Study, and
WHEREAS, after review, the Board deems it advisable to
approve said Plan of Work, with the terms and conditions being as
stated in said Plan, a copy of which is attached hereto and
incorporated herein by reference.
NOW, THEREFORE, BE IT RESOLVED by the Board of County
Commissioners of Weld County, Colorado, that the Plan of Work for
the Lone Tree Creek Flood Plain Management Study be, and hereby
is, approved.
BE IT FURTHER RESOLVED by the Board that the Chairman be, and
hereby is, authorized to sign said Plan of Work.
BOARD OF COUNTY COMMISSIONERS
ATTEST: WELD COUNTY, COLORADO
Weld County lerk and Recorder
and Clerk to the Board(t114-"(-4—)
J•cqu\. ' . -� .h son Chairman
�x /Tyl�isu� / a i=Tem
eputy County rk �I
APPROVED AS TO FORM: ene R. Brantner
EXCUSED DATE OF SIGNING - AYE
C.W. Kirby
( County ttor y
Y a u i
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860537.
r7rICI IL
COLORADO WATER
CONSERVATION BOARD
LANE TREE CREh"K
FLOOD PLAIN MANAGEMENT STUDY
PLAN OF WDRK
Prepared by the
U. S. DEPARTMENT OF AGRICULTURE
SOIL ODNSERVATION SERVICE
Denver, Colorado
in cooperation with the
Colorado Water Conservation Board
Weld County
April 1986
86053'
CONTENTS
Page
INTRODUCTION 1
LOCATION 2
PROBLEMS 2
NEED FDR STUDY 5
LIMITS OF STUDY AREA 5
TYPE AND INTENSITY OF INVESTIGATIONS 6
CONTENTS OF FINAL REPORT 7
COORDINATION AND RESPONSIBILITIES 9
SCHEDULING 9
FUNDING 10
PRINCIPAL WORK ITEMS 11
STUDY FDLLOW UP 12
ACTIVITY SCHEDULE 13
SIGNATURES 14
SE0537
INTRODUCTION
This plan of work for a flood plain management study of the lower 25
mile reach, of Lone Tree Creek, Weld County, Colorado was prepared by
representatives of the Colorado Water Conservation Board, Weld County, and
the Soil Conservation Service, United States Department of Agriculture.
The area to be studied includes the flood plains along Lone Tree
Creek through the irrigated areas in Weld County. Total study length is
25 miles. The purpose of this plan of work is to describe the need for, the
intended uses of the study findings, type and intensity of investigation,
interagency coordination, study responsibilities, scheduling, and funding
arrangements.
In Colorado, the Soil Conservation Service and several other federal
agencies, and private consulting firms are engaged in flood plain land use
studies. As coordinator for all water studies in the state, the Colorado
Water Conservation Board establishes this state's priorities and coordinates
schedules for these studies. The Colorado Water Conservation Board and the
Soil Conservation Service entered into a joint coordination agreement for
flood hazard analysis on January 27, 1972 (revised November, 1978).
The Soil Conservation Service, carries out flood plain management
studies under the authority of Section 6 of Public Law 83-566, in accordance
with Recommendation 9(c) Regulation of Land Use of House Document No. 465,
89th Congress, 2nd Session, and in compliance with Executive Order 11988,
Floodplain Management, effective May 24, 1977.
CEO:37
Location
Lone Tree Creek Basin is located in Wyoming and Colorado. The basin
area is apporoximately 590 square miles and extends 70 miles northwest of
Greeley, Colorado to approximately 14 miles southeast of Laramie, Wyoming.
The basin elevation at Ames Monument, Wyoming is 8,293 ft. (msl) and
falls to 4,590 ft. (meal) at Greeley, Colorado.
The basin area has approximately 82 square miles of irrigated cropland,
pasture, and hayland in Colorado; 108 square miles of non-irrigated cropland
in Colorado, and 400 square miles of rangeland in Wyoming and Colorado.
Problems
Even though the basin length extends approximately 70 miles northwest
of Greeley, the problem area of Lone Tree Creek is the first 25 miles above
the Junction with the South Platte River in Colorado.
Road damage is confined to culverts, bridges, and embankments where
Lone Tree Creek crosses the roads, and canals. In many cases the culverts
and bridges under the roads are too small to carry floodwater. This results
in debris plugging the culverts, or bridges, and floodwater overtopping the
roadway. The downstream side of the road fills are damaged by the
overtopping and the soil eroded from the road fill is deposited in the
fields below.
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PROJECT AREA
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3 SCALE IN PILES
Many of the natural drainage channels have been partially or completely
filled by land leveling for the irrigated cropland and by cultivation on
drylands. In other cases the channels have been restricted by farming
operations until there is very little channel capacity left for flood flows.
Large flows overtop existing channels and sometimes re-establish those that
have been altered by farming operations.
In the 25 miles above the South Platte River, there are several problem
areas:
1 . 2-Highway crossings.
2. 2-Railroad crossings.
3. 5-Irrigation canal crossings.
4. 30-County road crossings.
5. 5 miles of channel where Lone Tree Creek is parallel and
adjacent to the county roads.
The large snowpack on the upper portion of the Lone Tree Creek Basin,
extended the period of high flow into late summer in 1983. This long
duration of flow caused damage to the farmland, county roads, highways, and
canal crossings along the Creek. During normal snowpack and rainfall years
these runoff flows do not interfere with the normal operations cn farms,
roads, and canals.
Several irrigation canals that cross the lower Lone Tree Creek pick-up
the low flows of the Creek. The canals run at near capacity with irrigation
water during the high snowpack and rainfall years and do not have carrying
capacity to intercept additional high creek flows. As the flow proceeds
downstream, such as it did in 1983, there is a need for repair and
maintainance of the damaged areas along the Creek.
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Need for Study
Weld County has recognized the problem of inadequate channel and bridge
capacities. Before they can address the problem, they must know what
discharges may be expected in the watershed. The County does not have the
expertise to adequately study the basin and make valid predictions of
expected flows.
Given the range of discharges by frequencies, and alternative channel
capacities, the County can make a decision on future construction in the
basin. Also with this knowledge a coordinated approach can be made for
constructing new bridges and channel segments. The hydrologic an hydraulic
data will provide flood plain information to land users who have encroached
on the flood plain.
Limits of Study Area
The area of study includes the lower 25 mile reach of Lone Tree Creek
in Weld County, Colorado. The study begins at Lone Tree Creek's confluence
with the South Platte River. The upper end of the study area is where the
Pierce Canal crosses Lone Tree Creek.
The study area is located within USGS hydrologic unit 10190008.
SC v37
5
TYPE AND INTENSITY OF INVESTIGATION
Data such as flood history, photos, land use, and other pertinent
information will be collected for use in the study.
Flood hazard information for the 2-, 5-, 10-, 25-, and 100-year
frequency floods will be developed using existing conditions, at about 15
critical locations. The locations will be selected jointly by the SCS and
the county.
The 15 cross sections needed will be field surveyed.
The magnitude, elevation, and location of flooding for the designated
frequency floods will be developed frail hydrologic and hydraulic analyses
using standard Soil Conservation Service techniques and procedures.
An assessment will be made of the existing natural and beneficial
values served by the flood plain in the study area. Present flood damages
will be determined.
FY,033'7,"
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6
Flood control alternatives will be developed. These studies will
include the determination of the channel capacity and size by reach
throughout the study area. Structural designs will not be made.
Information will be developed for the county's use in guiding development in
the area. The hydraulic characteristics for the bridge opening will be
determined and can be used by the county in their bridge replacement
program. Alternate funding sources will be investigated. The most
promising sources will be listed.
CONTENTS OF THE FINAL REPORT
A preliminary draft of the report will be prepared by the Soil
Conservation Service and submitted for review to the officials of Weld
County, and the Colorado Water Conservation Board. The content,
organization and format of the report shall meet both state and Soil
Conservation Service guidelines to the extent possible. After reviews are
made, and ccements reconciled, a copy of the final report will be prepared
for publication.
The final report will include the following:
Part I
I. An introduction describing the needs for the study and authorities for
conducting the study.
II. A description of the study area including natural and beneficial
values served by the floodplain and present flood damage values.
III. A discussion of historic flooding, including excerpts from available I '
newspaper articles.
IV. A narrative with flood plain regulation information, flood insurance
information, recommendation for flood plain management, and
alternatives for reducing potential flood damages.
V. A technical section with the following:
7
A. Exhibits of flood profiles and representative cross-sections for
the selected flood frequencies.
B. Tabulation of discharge-elevation-frequency data for the 2-, 5-,
10-, 25- and 100-year floods.
C. Narrative on investigations, analyses, and technical data. The
size of the reports will be 11" x 8-1/2" with appropriate 11" x
17" foldout sheets for the engineering drawings.
D. Flood Control Alternatives.
A. Sizes and typical cross sections
B. Environmental Effects
E. Methods available to implement plan.
A. Federal Programs
B. State Programs
8
COORDINATION AND RESPONSIBILITIES
The Colorado Water Conservation Board is primarily responsible for
coordinating the study and providing information to other state, regional,
and federal agencies including the Office of Federal Insurance and Hazard
Mitigation, Federal Emergency Management Agency, the U.S. Army Corps of
Engineers, the U.S. Geological Survey, the U.S. Bureau of Reclamation, and
AR firms.
Weld County is responsible for obtaining permission to carry out field
surveys, providing public information coverage, and using the study findings
in its local flood plain management program. The Colorado Water
Conservation Board and Weld County representatives are responsible for the
distribution and interpretation of the flood plain management study reports
and providing continuing information and educational services following
completion of the studies.
The SCS is responsible for conducting the technical studies and
preparing the flood plain management report. The SCS will assist the
Colorado Water Conservation Board and Weld County in distributing the final
reports and the interpretations of flood hazard data needed in the
preparation and implementation of flood plain management.
SCHEDULING
Scheduling of the major study activities is shown on page 14. There
are several elements involved in each activity and work will be done
concurrently between activities. It is expected the duration of the study
will not exceed 10 months, and that the final report should be completed by
March 1987.
9
FUNDING
Total estimated cost for the study is $68,600. The cost will be shared
by the local sponsors and the Soil Conservation Service. The estimated cost
share for local sponsors is $9,000.
The Soil Conservation Service's share of the study cost is $59,600. Of
this amount, $48,000 will be needed in FY 86 and $11,600 will be needed in
FY 87. Funding for the Flood Plain Managemaent Assistance Program is though
regular agency appropriations.
Cost estimates based on the noted principal work items are as follows:
Local
Work Items Sponsors SCS
Floodplain Maps 3,000 0
Field Surveys 4,500 0
Assess Flood Plain Values 0 1,100
Technical Studies 0 17,000
Flood Control Alternatives 0 7,000
Computer Services 0 10,000
Preliminary Report Preparation 0 8,000
Final Report Preparation 0 6,000
Printing Final Report 0 2,500
Other Personel Services:
(Administration, Public Infor- 1,000 6,000
mation, Ingress & Egress Rights,
Historic Flooding Data, and
Future Development Data)
Travel 500 2,000
Total Cost 9,000 59,600
F ;.:s 7
10
PRINCIPAL WORK ITEMS
Collectively the Colorado Water Conservation Board and Wedl County
will:
1. Provide controled photo maps, scale 1" a 200' , of the channel area.
2. Secure all necessary rights of ingress and egress for engineering field
surveys and flood plain management studies.
3. Provide all needed field surveys, including about 15 cross sections.
4. Disseminate study information to the public and provide facilities for
public meetings.
In addition to the above, the Colorado Water Conservation Board will
coordinate all of the study activities between the sponsoring organizations.
The Soil Conservation Service will:
1. Conduct engineering field surveys for hydrologic and hydraulic
analyses.
2. Inventory and assess the existing national and beneficial flood plain
values.
3. Evaluate the existing flood plain and assign "N" values for each cross
section. The "N" values will be concured with by the Colorado WAter
Conservation Board before other techinal studies are started.
4. Conduct flood hazard technical studies: Hydrologic and hydraulic data
will be developed at selected points throughout the basin. Generally
the points will be about 2 miles apart.
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5. Regional hydrology curves will be developed for use to estimate peak
discharges per square mile of contributing area.
6. Develop at selected points alternative channel sizes and shapes to pass
the 2, 5, 10, 25 and 100 year flows.
7. Prepare an environmental evaluation of the proposed alternatives.
8. Work with the county to select recommended flood control alternatives
based on public inputs.
9. Prepare and distribute review draft of the report.
10. Prepare and print the final report.
11 . Prepare technical addenduns to support the study finding for the
Colorado Water Conservation Board, and Weld County.
12. Participate in interpretation and public information activities with the
state and county.
STUDY FOLLOW-UP
The SCS, in cooperation with the Colorado Water Conservation Board, will
provide follow-up assistance to Weld County as the last phase of the study.
Follow-up assistance includes interpretation of study findings and the
incorporation of the technical data into the County flood plain management
program. The Soil Conservation Service follow-up will be primarily as a
technical advisor and will not include land surveys, legal interpretations,
nor enforcement of regulations. The scheduling of assistance to interpret
the study finding will be coordinated through the Colorado Water
Conservation Board. Assistance is expected to be completed in FY 87
after distribution of the final report.
12
IANE TREE CREEK
FLOOD PLAIN MANAGEMENT STUDY
SCS Work Items
------------------ ---------------- ---f987-----
Iten -----1986
J JunAuPs Oc tidy,_ De J Fe
Hydrology Values ---
Hydrology Canputation --- ---
Hydraulic Computation ---- ----
Flood Plain Values Acces ----
Flood Control Alt.
Project Preparation
Reviews
Final Report �,— a --
_- -
January 1986
13
It is mutually agreed that this Plan of Study will be in effect only to
the extent that appropriated funds are available to all of the parties.
COLORADO WATER CONSERVATION BOARD:,
By _ 4LC&c�nn_ A1_dD&n 4Z
Tit e _
Date---6Latilie?�_-- ---- --
WELD COUNTY:
By
- -- -----
Ti Chairma , Board of County Commissioners
Date June 4 , 1986
SOIL CONSERVATION' SERVICE:
s
Title -5.41; Xeiresi
Date_
14
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STATE OF COLOMIA
COLORADO WATER CONSERVATION BOARD
Department of Natural Resources
423 State Comenngl Building
1313 Shorn an Street a
Donor.Colorado 80203
Mow:(3031•16-3441 .
Richard D.Lamm
September 13, 1983
.sziam**Dow
.. •
Devid W.Walks
Owl,Din
Mr. Sheldon Boone
State Conservationist
U. S. Soil Conservation Service
P. 0. Box 17107
Denver, CO 80217
Dear Sheldon:
Please find enclosed a copy of a resolution which was
unanimously passed by the Board at its September 8 meeting.
As you can see, the resolution supports and regpests a
comprehensive river basin_t„tudy for the LonelCreek basin in
Weld County. While the Board supports
that I make it clear that no funding
this v study, they the
Board either for the study itself or orathe lconstructioneof
any projects which may result from the study.
If there is anything else I or my staff need to do to
make the Board's support for this study known or if any other
follow-up actions are needed, please do not hesitate to call
upon us. We look forward to working with your staff and Weld
County on this study.
Sincerely,
J. William McDonald
Director
JWMcD:mm
Enclosure: as stated OAR C.aa.itrnnu.,,IMLC�tbDala .F.a ds,Ch airman
•11erbenM.Vats.,,, ViceOy6m,n
Maron.etic hard W.Iohmbn.M..,r,d,r ea v
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COLORADO WATER CONSERVATION BOARD
823 State Centennial Building ,
1313 Sherman Street
Denver, Colorado 80203
September 8, 1983
RESOLUTION
RESOLUTION RECOMMENDING A COMPREHENSD/E RIVER BASIN STUDY
INVESTIGATION FOR THE LONE TREE CREEK BASIN, CD COUNTY,
COLORADO.
WHEREAS, the Soil Conservation Service, U.S. Department of
Agriculture, has the authority under Section 6 of Public Law 566
to perform reconnaissance investigations for watershed protec-
tion, flood control, and water resources development for a river
basin; and
WHEREAS, the Lone Tree Creek Basin, Weld County, Colorado
has a history of flooding problems; and
WHEREAS, the floods of May, 1977, and June, 1983, have
demonstrated an urgent need to reestablish drainageways for
floodwater runoff; and
WHEREAS, the downstream reaches of the basin are extensively
developed for irrigated agriculture; and
WHEREAS, these agricultural lands are sane of the most pro-
ductive within Weld County and the State of Colorado; and
WHEREAS, parts of the basin lack drainage channels, Which is
impeding stormwater and irrigation wsistswater runoff; and
WHE ard has quested assistance in address County �theseels of floodi Weld County
from the Colorado Water Conservation Board. n9 problems
NOW THEREFORE, BE IT RESOLVED by the Colorado Water Conser-
vation Board in regular session assembled in Durango, Colorado,
on this 8th day of September, 1983, that it does request and rec-
ommend that a comprehensive river basin study of the said Lone
Tree Creek Basin be undertaken by the Soil Conservation Service,
U.S. Department of Agriculture.
BE IT FURTHER RESOLVED that the Colorado Water Conservation
Board will be the cooperating State agency for the study investi-
gation.
705
RES
BE IT FURTHER RESOLVED that the Secretary of the Board is
directed to send a certified copy of this resolution to the State
Conservationist, U.S. Soil Conservation Service, and the Board of
County Commissioners •of Weld County.
CERTIFICATE
I certify that the foregoing is a true and correct copy of a
resolution adopted by a majority vote of the members of the Colo-
rado Water Conservation Board in regular session assembled at
Durango, Colorado, on the 8th day of September, 1983 , at which a
quorum was present. 4
pi /4,44-7(41
William McDonald, Secretary
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UNITED STATES SOIL BLDG A, 3RD FLOOR, DHOC
DEPARTMENT OF CONSERVATION 2490 WEST 26TH AVENUE
AGRICULTURE SERVICE DENVER, COLORADO 80211
June 24 , 1986
Drew L. Scheltinga
Weld County Engineer
P.O. Box 758
Greeley , CO 80632-0758
Dear Drew:
Enclosed for your records is a signed copy of the Plan of Work
for the Lone Tree Creek , Flood Plain Management Study .
One of the first items of work will be to layout the needed field
surveys . I will contact you by phone to schedule a day for this .
Sincerely ,
"/".‘ f
JIM P. THORNTON
PB/WS Planning Staff Leader
enclosure
cc : Larry Lang , Colorado Water Conservation Board
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