WSP01053

• File Number: 8126.700
• Description: Arkansas River Coordinating Committee - Committees - Subcommittees
• State: CO
• Basin: Arkansas
• Water Division: 2
• Date: 1/1/1995
• Author: Unknown
• Title: District Enters Second Phase of Interruptible Supply Contracts Study
• Water Supply Pro - Doc Type: News Article/Press Release

...."

with C-BT and Windy Gap allotlees as an
integral pan of deciding how such a pro-
gram should be structured. In the coming
months, District staff will attend meetings
with allouees throughout the District to
provide Funher information and to obtain
feedback aboullhe program.
Gary Hoffner. the District's Agricultural
Resources Specialist who is responsible
for directing the study, assures water
users Ihat "only willing buyers and will-
ing sellers will enter into interruptible
supply contraCls. No C-BT allollee will be
forced in any way to enter into such an
agreement."

Agreement Components
The specific terms of lhe interruplible
supply contracts will be based on the
needs and concerns of the parties
involved, and will include:
. the amount of water to be transferred.
. the duration of the contract.
Interruptible supply contracts are
multi.year agreements for periods
as short as five years or as long as
40 years or more.
. the price paid for Ihe water.
The buyer could pay the seller an
"option payment" in return for
making water available under the
interruptibLe supply contract and an
"exercise payment" for the water
itself when actually trallsferred to
rhe buyer.
adjustment of price over time.
. the conditions that trigger transfer
of the water.
the due date for notice to the 'seller
that the waler will be transferred 10
the buyer in that year.
. who will pay assessments on the
water.
Typical!:..,. whoever uses the waler in
a given year pa.\.'s. the assessme1lCs
for that year.
other tenns that the parties agree on
to meet their particular needs.

For further information, or. to obtain a
copy of the report on interruptible sup-
ply contracts prepared for tbe District
by Pinnes, contact Gary Hoffner or
Brian Werner at [phone]. .

WATERNEWS/WINTER 1995

Conclusions of Canal
Treatment Study Released

The Nonhern Colorado Water Conser-
vancy District (District) has received
the final report from the Colorado Divi-
sion of Wildlife (CDOW) for a study tar-
geting algae treatmenl procedures for
maintenance on Colorado-Big Thompson
(C-BT) Project canals. The report is the
culmination of a two-year etTon among
lhe CDOW, Colorado Stale University
(CSU), and the District. The report con-
cludes that the District's algae treatment
program is not responsible for past fish
kills in the Big Thompson River.
This closes the book on
District involvement in the
puzzling fish kills which
occurred in the Big
Thompson River in Octo-
ber 1990 and August 1992.
The District's algae treal-
menl procedures were tar-
geted for study because the
Hansen Feeder Canal
(HFC) supplies water to
the Big Thompson River
near the mouth of the Big
Thompson Canyon. The
District and the U.S. Bureau of Reclama-
tion have used copper sulfate to control
algal growth in C-BT canals for 27 years.
, Afler the 1990 incident. the DistriCI
~oopera(ed in an investigation with the
CDOW and City of Loveland to deter-
mine if canal maintenance activities had
contributed to the fish fatalities. That
investigation revealed that the District's
activities had nothing to do with the prob-
lem~ When a similar fish kill occurred in
1992. some members of the public ques-
tioned whether the Districr"s use of cop-
per sulfate for algae comrol in the HFC
was responsible. After the investigation.
the CDOW. along with the Larimer
County Departmem of Hcahh. found no
connection between copper sulfate treat-
ments and the fish kill.
As a precaution. the District suspended
all anti-algal treatments in the HFC from
August 27-December 10, 1992. Atlha!
time, Roger Sinden, Head of the Dis-
trict's Distribution Systems Depanmenl.

stated "we decided to SlOP treating just in
case there might be negative effects on
the fish population. We were pretty sure
the copper sulfale was safe. but decided
10 study the possibility that it was nol."
As an extension of that philosophy. the
District then entered into an agreement
with the CDOW and CSU to hell' fund a
study on algae treatment procedures.
Colorado State University researchers
and graduate students under the direction
of Dr. John Stednick. assisted the CDOW
with the initial field work for the study,
which concluded in Octo-
ber 1993. This work
included sampling water
in various locations along
the HFC for copper con-
lent; sampling of canal
sediments for copper con-
tent; analysis of copper
sulfate's effectiveness for
algae control; and an~lysis
of the toxicity of copper
sulfate for fish.
The CDOW then com-
menced the next phase of
the study lO expand on infonnation
regarding the concentration amounts of
copper and its duration in the canal and
Big Thompson River waters resulting
from the Dislrict's copper sulfate treat-
ments. Other aspects studied included
copper toxicity lO fish which were
exposed for shan periods of time: toxici-
ty of copper in waters that are soft and
have low alkalinity (both characteristics
of C.BT water and Big Thompson
River water during spring runoff and
summer); IOxicity of copper to fish From
exposure caused when the District releas-
es copper sulfale imo the HFC; and the
potential for using Cutrine-Plus as a less
toxic alternative to copper sulfate.
The final sludy results were released in
August 1994. Patrick Davies and Stephen
Brinkman. CDOW staff memhers and
authors of the study report, write thai
""the most imponant faclor innuencing
the short-tenn acute toxicity of copper is
(continued on page IS)

The report concludes
that the District's algae
treatment program is
not responsible for past
fish kills in the Big
Thompson River.

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