s333.91 M26prar

1992

1992 ANNUAL REPORT

to the GOVERNMENTS OF CANADA, UNITED STATES,

SASKATCHEWAN AND MONTANA

iSTATE DOCUMENTS COLLECTION

FEB 2 e 1994 MONTANA STATE LIBRARY

1515 E. 6th AVE. HELENA, MONTANA 59620

POPLAR RIVER

BILATERAL MONITORING COMMITTEE

CX)VERING CALENDAR YEAR 1992

Poplar

December 1993
3 0864 1004 5765 7
1992 ANNUAL REPORT

to the

GOVERNMENTS OF CANADA, UNITED STATES,

SASKATCHEWAN AND MONTANA

by the

POPLAR RIVER BILATERAL MONITORING COMMITTEE

covering calendar year 1992

December 1 993

Poplar River Bilateral Monitoring Committee

Department of State Washington, D.C., United States

Governor's Office State of l\yiontana Helena, Montana, United States

Department of External Affairs Ottawa, Ontario, Canada

Saskatchewan Environment and

Resource Management

Regina, Saskatchewan, Canada

Ladies and Gentlemen:

During 1992, the Poplar River Bilateral Monitoring Committee continued to fulfill the responsibilities

assigned by the governments under the Poplar River Cooperative Monitoring Agreement dated September 23, 1980. Through the exchange of Diplomatic Notes, on March 12, 1987, the Arrangement was extended to March 1991. In July 1992, another exchange of Diplomatic Notes extended the Arrangement retroactively from March 31, 1991 to March 31, 1996. In addition, the Arrangement was modified to terminate quarterly exchange of data and substitute an annual exchange of data.

The enclosed report summarizes current conditions and compares them to guidelines for specific

parameter values that were developed by the International Joint Commission under the 1977

Reference from Canada and the United States. After examination and evaluation of the monitoring

information for 1992, the Committee finds that the measured conditions meet the recommended

objectives. However, the Committee notes that flow-weighted concentration of total dissolved solids

in streamflow in the East Poplar River at the International Boundary continues to increase and is approaching the long-term objective of 1 ,000 milligrams per liter

During 1992, monitoring continued in accordance with Technical Monitoring Schedules outlined in the 1991 Annual Report of the Poplar River Bilateral Monitoring Committee.

Herein is the 12th Annual Report of the Poplar River Bilateral Monitoring Committee. This report discusses the Committee activities of 1992 and presents the proposed monitoring schedule for 1993.

Yours sincerely.

.ft i\UJLJ

Me A. Moreland

fhairman. United States Section

R.A. Halliday

Chairman, Canadian Section

/C '^

'-f'-r

Gary Fritz Member, United States Section

D.D. Nargang

Member, Canadian Section

TABLE OF CONTENTS

Highlights for 1992 iii

1.0 Introduction 1

2.0 Committee Activities 2

2.1 Membership 2

2.2 l\/leetings 2

2.3 Review of Water-Quality Objectives 3

2.4 Data Exchange 5

3.0 Water and Air: Monitoring and Interpretations 5

3.1 Poplar River Power Station Operation 5

3.2 East Poplar River 5

3.2.1 Streamflow 5

3.2.2 Apportionment 6

3.2.3 Minimum Flows 7

3.2.4 On-Demand Release 8

3.2.5 Water Quality 8

3.2.5.1 Total Dissolved Solids 8

3.2.5.2 Boron 11 3.2.5.3 Other Water-Quality Variables 13

3.3 Groundwater 15

3.3.1 Operations 15

3.3.2 Ground-Water Levels 15

3.3.2.1 Saskatchewan 15

3.3.2.2 Montana 17

3.3.3 Ground-Water Quality 19

3.3.3.1 Saskatchewan 19

3.3.3.2 Montana 25

3.4 Cookson Reservoir 26

3.4.1 Storage 26

3.4.2 Water Quality 27

3.5 Air Quality 28

3.5.1 Saskatchewan Environment and Resource Management 28

3.5.2 SaskPower Corporation 28

3.6 Quality Control 29

3.6.1 Streamflow 29

3.6.2 Water Quality 29

4.0 References Cited 31

ANNEXES

1 .0 Poplar River Cooperative Monitoring Arrangement, Canada-United States A1 -1 2.0 Poplar River Cooperative Monitoring Arrangement, Technical Monitoring

Schedules, 1993, Canada-United States A2-1

3.0 Recommended Flow Apportionment in the Poplar River Basin A3-1

4.0 Metric Conversions A4-1
TABLES

Table 2.1 Recommended Water-Quality Objectives 4

Table 3.1 Recommended Water-Quality Objectives and Excursions, 1992 Sampling

Program, East Poplar River at International Boundary 14

Table 3.2 Water-Quality Statistics for Water Pumped from Supplementary Water Supply

Project Wells Sampled at Site "C3" on Girard Creek 20

Table 3.3 Water-Quality Statistics for Water Pumped from Soil Salinity Project Wells Sampled at the Discharge Pipe 21

Table 3.4 Cookson Resen/oir Storage Statistics for 1992 26

Table 3.5 Streamflow Measurement Results for June 17, 1992 29

FIGURES

Figure 3.1 Discharge during 1992 as Compared with the Median Discharge for 1961-1990

for the Poplar River at the International Boundary 6

Figure 3.2 Flow Hydrograph of the East Poplar River at the International Boundary 7

Figure 3.3 TDS Concentrations for 1992 Grab Samples from East Poplar River at International Boundary 9

Figure 3.4 Three-Month Moving, Flow-Weighted TDS Concentration for East Poplar River

at International Boundary 9

Figure 3.5 Five-Year Moving, Flow-Weighted TDS Concentration for East Poplar River at International Boundary 10

Figure 3.6 Boron Concentrations for 1 992 Grab Samples from East Poplar River at International Boundary 11

Figure 3.7 Three-Month Moving, Flow-Weighted Boron Concentration for East Poplar

River at International Boundary 12

Figure 3.8 Five-Year Moving, Flow-Weighted Boron Concentration for East Poplar River

at International Boundary 12

Figure 3.9 Drawdown for Hart Seam Aquifer as of December 1992 16

Figure 3.10 Cone of Depression in the Empress Sands Due to the Salinity Project as of December 1992 18

Figure 3.11 Hydrographs of Selected Wells 19

Figure 3.12 Total Dissolved Solids in Samples from Montana Monitoring Wells 25

Figure 3.13 Cookson Reservoir Mean Daily Water Levels for 1992 and Median Monthly Water Levels for 1981 -1991 27
HIGHLIGHTS FOR 1992

The Poplar River Power Station completed its ninth full year of operation in 1 992. The two 300-

megawatt coal-fired units generated 4 692 000 gross megawatt-hours (MW/h) of electricity, 103

percent from 1991 and 102 percent from 1990. In 1992, the average capacity factor for Unit No. 1 was 92.8 percent and the average capacity factor for Unit No. 2 was 88.2 percent.

Monitoring information collected in both Canada and the United States during 1992 was exchanged

in the spring of 1993. In general, the sampling locations, frequency of collection, and parameters

met the requirements identified in the 1992 Technical Monitoring Schedules set forth in the 1991

annual report.

Regional drought conditions persisted during 1992 resulting in below nonnal streamflows. The

March to October recorded flow of the Poplar River at the International Boundary for 1992 was 2 080

cubic decametres (dam^) which was 21 percent of the 1931 to 1991 median seasonal flow. The

1992 recorded flow volume of the East Poplar River at the International Boundary was 1 860 dam^.

This volume Is 54 percent of the median annual flow since completion of Morrison Dam in 1975. The

on-demand release, in accordance with the apportionment recommendations of the International

Joint Commission (IJC), entitled Montana to 370 dam'^ for 1991-92 to be delivered between May 1

and May 30, 1 992. A volume of 480 dam^ was delivered during this period.

iii

1.0 INTRODUCTION

The Poplar River Bilateral Monitoring Committee was authorized for an initial period of five years by

the Govemments of Canada and the United States under the Poplar River Cooperative Monitoring

Arrangement dated September 23, 1980. A copy of the Arrangement is attached to this report as Annex 1 . On March 12, 1 987, the Arrangement was extended by the Govemments for four years to March 1991 . In July 1992, the Arrangement was further extended retroactively from March 31 , 1 991

to March 31, 1996 following a request from the Committee in 1991. A more detailed account of the

historical background of the Arrangement is contained in the 1990 Annual Report of the Poplar River

Bilateral Monitoring Committee.

The Committee oversees monitoring programs designed to evaluate the potential transboundary

impacts from SaskPower's (formeriy Saskatchewan Power Corporation) coal-fired themnal

generating station and ancillary operations near Coronach, Saskatchewan. Monitoring is conducted

in Canada and the United States at or near the International Boundary for quantity and quality of

surface and ground water and for air quality. Participants from both countries, including Federal,

State and Provincial agencies, are involved in monitoring.

The Committee submits an annual report to Governments which summarizes the monitoring results,

evaluates apparent trends, and compares data to objectives or standards recommended by the

international Joint Commission to Govemments, or to relevant Federal, State or Provincial

standards. The Committee reports to Govemments on a calendar year basis. This report is the

twelfth in the series. The Committee is also responsible for drawing Government's attention to

definitive changes in monitoring parameters which may require immediate attention.

A responsibility of the Committee is review of the adequacy of monitoring programs in both countries and recommending changes in Technical Monitoring Schedules to Govemments. The Schedules

are updated annually to document changes in monitoring locations, sampling frequencies,

parameter lists, and analytical techniques. The Technical Monitoring Schedules listed in the annual
2

report (Annex 2) are given for the forthcoming year. The Committee reviews and proposes changes

to the Technical i\/Ionitoring Schedules as information requirements change.

2.0 COMMITTEE ACTIVITIES

2.1 Membership

The Committee is composed of representatives of the Federal Governments of the United States and Canada, the State Government of Montana, and the Provincial Government of Saskatchewan.

In addition to the representatives of Govemments, two ex-officio members serve as local

representatives for the State of Montana and the Province of Saskatchewan. '

During 1992, members of the Committee included: Mr J.R. Knapton, U.S. Geological Survey,

United States representative and CoChairperson; Mr R.A. Halliday, Environment Canada,

Canadian representative and CoChairperson; Mr A. Wittich, Govemor's Office, Montana

representative; Mr D.D. Nargang, Saskatchewan Environment and Resource Management,

Saskatchewan representative; Mr C.W. Tande, Daniels County Commissioner, Montana local exofficio representative; and Mr J.R. Totton, Reeve, R.M. of Hart Butte, Saskatchewan local ex-officio

representative.

2.2 Meetings

The Committee met on June 2 and 3, 1 992, in Coronach, Saskatchewan. Delegated representatives

of Govemments except the representative from the State of Montana attended the meeting. Neither

of the ex-officio members were in attendance. In addition to Committee members, several technical

advisors representing Federal, State and Provincial agencies participated in the meeting. During the

meeting, the Committee reviewed the operational status of the power plant and mine; examined data

collected in 1991 including surface-water quality and quantity, ground-water quality and quantity, and

air quality; established the Technical Monitoring Schedules for 1992; considered a draft report on
3

quality-assurance results; discussed proposed changes in water-quality objectives; and toured the

power plant, ash lagoons, mine, and other ancillary facilities. The Committee also prepared the first

draft of the 1991 Annual Report to Govemments.

2.3 Review of Water-Quality Objectives

The International Joint Commission in its Report to Govemments, titled "Water Quality in the Poplar

River Basin," recommended that the Committee "periodically review the water-quality objectives

within the overall Basin context and recommend new and revised objectives as appropriate." In

1 991 , the Committee undertook a review of water-quality objectives. A subcommittee composed of

Mr. J.R. Knapton, U.S. Geological Survey; Mr J.-G. Zakrevsky, Environment Canada; Mr A.

Horpestad, Montana Department of Health and Environmental Sciences; and Mr D.D. Nargang,

Saskatchewan Environment and Resource Management, was formed to review and recommend

changes in water-quality objectives.

The subcommittee examined the entire data base collected during the last eleven years of

monitoring. This data base has led to a better understanding of background conditions in the basin

and documented the presence or absence of trends in monitored constituents.

The subcommittee agreed that dissolved trace elements should be dropped from the water-quality

objectives. The group reached consensus that total trace element concentrations provided more

meaningful information but that differences in laboratory analytical procedures and field techniques

would have to be investigated to determine comparability of data.

The subcommittee noted that mercury concentrations in tissue from fish in Cookson Reservoir are

less than Canadian consumption guidelines. However, the subcommittee recommended that fishery

experts be consulted before a decision is made to drop the objective.
The subcommittee also reviewed the water-quality objectives for 5-year and 3-month flow-weighted

concentrations for total dissolved solids and boron. Although the subcommittee agreed that

calculation procedures to determine flow-weighted concentrations are time consuming and probably

scientifically questionable, no consensus was reached on alternative objectives or procedures.

Recommendations of the subcommittee are summarized in Table 2.1

.

Table 2. 1 Recommended Water-Quality Objectives.

PARAMETER
2.4 Data Exchange

The Committee is responsible for assuring exchange of data between governments. The exchange

of monitoring information was initiated in the first quarter of 1981 and was an expansion of the

informal quarterly exchange program initiated between the United States and Canada in 1976. Until

1991 , data were exchanged on a quarterly basis. At the request of the Committee, the United States and Canada agreed to replace the quarterly exchange of data with an annual exchange effective at

the beginning of the 1 992 calendar year

Henceforth, data will be exchanged once each year as soon after the end of the calendar year as

possible. However, unusual conditions or anomalous information will be reported and exchanged

whenever warranted. No unusual conditions occurred during 1992 which would warrant special

reporting.

3.0 WATER AND AIR: MONITORING AND INTERPRETATIONS

3.1 Poplar River Power Station Operation

In 1992, the average capacity factor for Unit No. 1 was 92.8 percent. The average capacity factor for

Unit No. 2 was 88.2 percent. The capacity factors are based on the maximum power generation

rating of 297.8 MW/h for Unit No. 1 and 294 MW/h for Unit No. 2. Total power generated from both

units was 4 692 000 gross megawatt-hours which is about 103 percent of 1991 power and 102

percent of 1 990 power

3.2 East Poplar River

3.2.1 Streamflow

Streamflow in the Poplar River basin was below normal in 1992. The f^arch to October recorded

flow of the Poplar River at the international Boundary, an indicator of natural flow in the basin, was

2 080 cubic decametres which was 21 percent of the 1931 to 1991 median seasonal flow. For the
6

sixth consecutive year, the flow was below normal. A comparison of 1992 monthly mean discharge

with the 1961-90 median discharge is shown in Figure 3.1.

o

oLxJ

(/) a:

Ld

CL

C/O UJ

en

1.000

0.800

0.600 o

m

o

z

(jj o

<X

o

Q

0.400

0.200

0.000

MEDIAN OF MONTHLY MEAN DISCHARGE FOR 1961 -1990 J MONTHLY MEAN DISCHARGE FOR 1 992

:^^

MAR APR MAY JUN JUL AUG SEP OCT

Figure 3.1 Discharge during 1992 as Compared with the IVIedian Discharge

from 1961-1990 for the Poplar River at the International Boundary.

The 1992 recorded flow volume of the East Poplar River at the International Boundary was 1 860

dam-^. This volume is 54 percent of the median annual flow since the completion of Morrison Dam in

1975.

3.2.2 Apportionment

In 1976 the International Souris-Red Rivers Engineering Board, through its Poplar River Task Force,

completed an investigation and made a recommendation to the governments of Canada and the

United States regarding the apportionment of waters of the Poplar River basin. Although not

officially adopted by the two countries, the Poplar River Bilateral Monitoring Committee has adhered
to the Apportionment Recommendations in each of its annual reports. Annex 3 contains the

apportionment recommendation.

3.2.3 Minimum Flows

The recorded volume of the Poplar River at the International Boundary from March 1 to May 31,

1992 was 1 460 dam-^. Based on IJC recommendations and the assumption that the recorded flow is

the natural flow, the United States was entitled to a minimum discharge on the East Poplar River of

0.028 cubic metres per second (m^/s) for the period June 1, 1992 to May 31, 1993. The minimum

flow for the period January 1 to May 31, 1992 had previously been determined on the basis of the

Poplar River flow volume for March 1 to May 31 , 1 991 . A hydrograph for the East Poplar River at the

International Boundary and the minimum flow as recommended by the IJC are shown in Figure 3.2.

Daily flows during 1992 were above the recommended minimum at all times with the exception of

December 29, 30, 31, 1992. Extremely cold temperatures reduced the flow to 0.027 m^/s on these

days.

T 1 1 1 1 1 1 r

/ 0.028 m3/t

Apportionment recommendation for minimum flow

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 1992

Figure 3.2 Flow Hydrograph of the East Poplar River at the International Boundary.
3.2.4 On-Demand Release

In addition to the minimum flow, the IJC apportionment recommendation entitles Montana to an on- demand release to be delivered during the twelve month period commencing June 1, 1991. Based

on the runoff volume recorded at the Poplar River at the Intemational Boundary gaging station during

the March 1 to May 31, 1991 period, Montana was entitled to a release of 370 dam"' from Cookson

Reservoir Montana requested this release to be made between May 1 and May 30, 1992. A

volume of 480 dam^ was delivered during this period.

3.2.5 Water Quality

The 1981 report by the IJC to Governments recommended:

For the March to October period, the maximum flow-weighted concentrations should

not exceed 3.5 milligrams per liter (mg/L) for boron and 1 500 mg/L for total dissolved

solids for any three consecutive months in the East Poplar River at the International Boundary. For the March to October period, the long-term average of flow-weighted

concentrations should be 2.5 mg/L or less for boron, and 1 000 mg/L or less for total dissolved solids in the East Poplar River at the International Boundary.

The Bilateral Monitoring Committee adopted the approach that, for the purposes of comparison with

the proposed IJC long-term objectives, the boron and total dissolved solids (TDS) data are best

graphically plotted as 5-year moving flow-weighted concentrations (FWCs) which were advanced one month at a time.

3.2.5.1 Total Dissolved Solids

TDS data for grab samples collected by Environment Canada and the U.S. Geological Survey in

1992 are shown in Figure 3.3. TDS ranged from 743 mg/L (March 16) to 1 286 mg/L (May 19). The

short-term objective for TDS is 1 500 mg/L. A time plot of the 3-month moving FWCs for TDS is

presented in Figure 3.4. No exceedances of the objective have been observed during any 3-month

period since 1975. The 3-month FWCs remained confined within a narrow range centered around a mean of approximately 1 000 mg/L during 1992.
1300

1200

1100 3 1000 m

Q

H 900

800 -

700

- • • -

1992 N 1993

Figure 3.3 TDS Concentrations for 1992 Grab Samples from East Poplar River

at International Boundary.

1600

1500

1400

1300

1200

1100

1000 900

800

700

600

500 400

300

200

100

I

'

I '—1 'I

' I

'

1 '

I ' I

' 1 ' I ' I

' I'

I

' I' r Short-Term Objective (1500 mg/L)

from sample analysis, from regression

_l I I I I I 1974 1975 1978 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 Year

Figure 3.4 Three-Month Moving, Flow-Weighted TDS Concentration for East

Poplar River at International Boundary.
10

Five-year FWCs for TDS (Figure 3.5) remained below the long-term objective of 1 000 mg/L. An

increase in the 5-year FWCs to approximately 955 mg/L was observed in 1992. A 200-mg/L

increase had previously occurred in early 1988 and had been maintained through 1989 and 1990. The 1991 rise in FWCs corresponds to depressed spring flows in the East Poplar River A similar

increase in TDS was seen during mid-1987. Relatively low spring discharges have occurred since

1 984. If this trend continues, it is expected that FWCs will reach the 1 000 mg/L objective. The TDS

increase can be explained in part by salt build-up in Cookson Reservoir as a result of water being

used for cooling. Forced evaporation causes salts to concentrate within the reservoir This process

is further driven by drought conditions which prevailed over the last half of the data record (Lang and

Jones, 1988). In addition, low-flow conditions (when flows are derived largely from ground-water

sources) likely increase TDS concentrations and yields a positive TDS trend in the data.
11

3.2.5.2 Boron

During 1992, boron concentrations in the East Poplar River at the international Boundary varied from

1.40 mg/L (March 16) to 2.34 mg/L (May 19) (Figure 3.6).

2.4

<J 2.0

OB6

^— 1.8 a

oI

1-6

1.4

1.2

- • • • • -

• • •

- •

1992 N 1993

Figure 3.6 Boron Concentrations for 1992 Grab Samples from East Poplar River

at International Boundary.

Three-month boron FWCs for the period of record are shown in Figure 3.7. The short-term objective

of 3.5 mg/L boron was not exceeded for the period 1975-1992. The similarity in shape between the TDS and boron plots (Figures 3.4 and 3.7) is a strong indication of the influence of discharge on FWC functions.

The 5-year boron FWCs, displayed in Figure 3.8, remained well below the long-term objective of 2.5 mg/L boron. From mid-1988 to the end of 1990, there was a slight increase in the 5-year boron FWC. The 5-year boron FWC increased slightly from 1 .90 mg/L in 1991 to approximately 1 .95 mg/L.

The 5-year calculations for boron were significantly influenced by discharge in exactly the same way

as was TDS.
12

<

4.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0.0

-I—'—I—'—I—'—I—'—I

'—I—'—

r

1—'—I—'—I—'—I—'—I—'—I—'—

r

Short-Term Objective (3.5 mg/L)

from sample analysis from regression

I I I I 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 Year

Figure 3.7 Three-Month Moving, Flow-Weighted Boron Concentration for East Poplar River at International Boundary.

—\—I—i—I—I—'

\—I—I—'—I—I—

r

Long-Term Objective (2.5 mg/L)

J I I I I 1 L

1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 Year

Figure 3.8 Five-Year Moving, Flow-Weighted Boron Concentration for East

Poplar River at International Boundary.
13

The relation between boron and specific conductance at the East Poplar River sampling location

during the period 1975-1992 is described by the equation:

boron - (0.00144 x specific conductance) - 0.218

(r2 = 0.69, n = 449)

The increase in boron, as was the case with TDS, can be explained by evaporative loss of water

brought on by the drought conditions and the use of water for cooling, both intensifying natural

evaporation from Cookson Reservoir

3.2.5.3 Other Water-Quality Variables

Table 3.1 lists the multipurpose water-quality objectives for the East Poplar River in the Intemational

Boundary, recommended by the Intemational Poplar River Water Quality Board to the IJC. A single

excursion of the multipurpose objectives occurred in 1992. On January 15th, a dissolved oxygen measurement of 2.4 mg/L was below the 4.0 mg/L objective. It is believed that extensive ice cover,

coupled with low-flow conditions, drastically inhibited the aeration process.

Environment Canada monitored the East Poplar River for phenoxy acid herbicides and

organochlorine compounds during 1992. Trace concentrations of 2,4-D (in two of five samples),

T^BHC (in one of five samples), a-BHC (in one of five samples) and Dicamba (in one of five samples)

were recorded. The presence of these compounds in prairie surface waters is well documented

(Integrated Environments Limited, 1991). All other organic compounds monitored were below

analytical detection limits.
14

Table 3.1 Recommended Water-Quality Objectives and Excursions, 1992 Sampling Program, East

Poplar River at Intemational Boundary

Parameter
15

3.3 Groundwater

3.3.1 Operations

In 1992, as part of the Supplementary Water Supply Project, 21 wells were in operating status.

Operation of these wells resulted in a total of 5 225 dam^ of ground water being pumped. A regional

network of 1 71 piezometers was monitored as part of this project.

Currently, there are eight pump wells installed as part of the Soil Salinity Project. These wells

produced a total of 942 dam^. However, 95 percent of this water was produced from PW87103 and

PW87104 on the east side of the East Poplar River and PW90108 on the west side of the East

Poplar River.

3.3.2 Ground-Water Levels

3.3.2.1 Saskatchewan

As can be seen in figure 3.9, there appears to have been a slight general expansion in the cone of

depression in 1992. Of particular note is the expansion of the cone along the Montana border The

cone has shifted south only slightly, but it has spread out along the border As a result, the 1 -metre drawdown contour is approaching the border along a front from Section 1, Township 1, Range 27, West of 2, to Section 1 , Township 1 , Range 28, West of 2, and in places is less than 1 kilometre from

the border This change may be due in part to the replacement of border piezometers M506 and

M510. The old piezometers were not yielding reliable data which probably influenced the

interpretation of previous drawdown maps. Based on the drawdowns seen on the 1 992 map, it is

clear that some drawdown will be occurring along the border in Montana. However, these drawdowns are estimated to be less than 1 metre. This confirms the drawdowns noted by state

officials in Montana in piezometers they measured in 1991.
16

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17

Figure 3.10 illustrates the extent and magnitude of the cone of depression in the Empress Sands as a result of the Soil Salinity Project. The pumpage is resulting in drawdowns of approximately 1 metre

at the International Boundary in Sections 4, 5, and possibly 3, of Township 1 , Range 26, West of 2. The projected goal for achieving drawdowns in the order of 2 to 3 metres has now been achieved,

and therefore future pumping should be relatively stable subject to water levels in Cookson

Reservoir

3.3.2.2 Montana

During 1992, water levels continued to decline in monitoring wells located in Montana with the

exception of wells 2, 8-9, 11, and 21. At the International Boundary, water levels have declined

approximately 0.6 metres in wells 5 and 6 and about 1 metre in well 10. Well 10 is responding to pumpage from the Hart coal seam and probably pumpage from Soil Salinity Project wells along the

East Poplar River downstream from Morrison Dam.

Hydrographs of selected wells which monitor water levels in the Hart coal seam are shown in figure

3.11.
18

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3 3

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ul
19

c

g

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2445-

Jan-79 Jan-81 Jan-83 Jan-85 Jan-87 Jan-89 Jan-91 Jan-93 Jan-95

Figure 3.11 Hydrographs of Selected Wells.

3.3.3 Ground-Water Quality

3.3.3.1 Sasi(atchewan

The water quality from the Supplementary Water Supply Project discharge points has been

consistent with no trends indicated. A summary of the more frequently tested parameters during

1992 is provided in Table 3.2. Statistical averages of the results since January 1990 are included in

this table.
20

Table 3.2 Water-Quality Statistics for Water Pumped from

Supplementary Water Supply Project Wells Sampled

at Site "C3" on Girard Creek.
21

Table 3.3 Water-Quality Statistics for Water Pumped from Soil

Salinity Project Wells Sampled at the Discharge Pipe.
22 used to detect leachate movement and calculate seepage rates. In 1992, 15 new piezometers were

installed to obtain additional information on leachate effects and seepage from the ash lagoons.

The piezometric surface for the oxidized strata shows a ground-water mound that has developed

beneath the ash lagoons. The ground-water mound extends from the east side of Ash Lagoon No.

2, where a 6-metre increase has been noted, to the west side of the Polishing Pond, where levels have increased about 4 metres. The new oxidized-till piezometers installed along Dyke B confirm

the ground-water mound that has developed. The oxidized-till piezometers closer to the reservoir have shown a decreasing trend in piezometric levels reacting to lower reservoir water levels.

The largest changes in chloride and boron concentrations have occurred where the water levels have changed the most. This would be expected because changing water levels suggest leachate movement. Increasing boron concentrations on the east and south sides of Ash Lagoon No. 2,

together with decreasing chloride concentrations, suggests leachate influence. On the west side of

the Polishing Pond, boron concentrations have not changed significantly.

Little change in boron or chloride concentrations has been noticed in samples from most of the

oxidized-till piezometers located by the reservoir The only significant change in samples from any of

these piezometers has been at C719 where chloride concentrations have decreased by 96 mg/L

since 1983, to a concentration of 14.7 mg/L in 1992. This piezometer is beside the reservoir and the

change in quality is due to the lower water levels of the reservoir rather than ash-lagoon influence.

During the 1991 review, a ground-water mound was concluded to have developed in the unoxidized

till similar to that in the oxidized till, extending from the east side of Ash Lagoon No. 2 to the west

side of the Polishing Pond. The ground-water mound was known not to be continuous because some unoxidized-till piezometers within the mound area had no increase in piezometric level. The new piezometers installed along Dyke B (C868C, C869C, and C871C) provided some valuable

infonnation. These piezometers located in the middle of the lagoon area are illustrating a
23

decreasing trend in piezometric levels matching decreasing reservoir levels. This new infonnation

would suggest that the ground-water mound in the unoxidized till is not general but likely occurs in

unconnected pockets. A review of boron and chloride concentrations does not show any strong

trends.

The piezometric surface of the Empress gravels indicate a regional flow from northwest to southeast

below Morrison Dam. Since 1983, the closer an Empress piezometer is to the reservoir, the larger

the decrease in water level. Around the lagoon area there is a noticeable drop in piezometric level at

the north end of Ash Lagoons No. 1 and No. 2, and a mound has developed at the east end of Ash

Lagoon No. 3 North. The mound on the east side of Ash Lagoon No. 3 North is likely due to upper

horizon influences. Results for the Empress gravel do not indicate any seepage activity with the

majority of piezometer wells showing little change in boron or chloride concentrations.

Piezometer series C775 is located at the southeast corner of Ash Lagoon No. 3 North. Until 1992,

chloride concentrations have only varied in samples from the oxidized-till piezometer C775A. For the

last two years, water levels in the oxidized-till piezometer C775B, the unoxidized-till piezometer

C775C, and the Empress-gravel piezometer C775D have increased. This is especially significant in C775B where the level has increased 6 metres in the last year and boron concentration has

increased to 6.6 mg/L in 1992. The changes seen for the piezometers in the area are significant but more data will be needed to reach any firm conclusions.

Sand-lense piezometers C712B, C766, and C767 are located between the Polishing Pond and the

cooling water canal. C767 is located on top of Dyke G. C766 and C712B are located at the top of Dyke G.

A review of the boron concentrations for samples from C766 shows an increasing trend until October

1988 when levels peaked at 12.6 mg/L. Boron concentration decreased to 6.99 mg/L in April 1990,
24

started increasing again, and peaked at 23.7 mg/L at the end of 1991. In 1992, the boron

concentrations remained stable at about 25 mg/L.

Until April 1988, the boron concentration for samples from C767 was increasing and peaked at 49.4

mg/L. From this peak, the boron concentration has steadily decreased. By the end of 1991 the

boron concentration had leveled off t>elow 4 mg/L and remained at this concentration through 1992. The reduction in boron concentrations for samples from C767 to background concentrations suggest a leachate plume and not a continuous front.

Piezometer C712B has been monitored for several years. Historically, boron concentrations have

been below 1 mg/L. In mid-1987, increasing boron concentrations were noted with the concentration

peaking in April 1992 at 26.6 mg/L.

Chloride concentrations trended down in samples from C712B to 50 mg/L in 1988 from over 200

mg/L in 1984. Since 1988, chloride concentrations have changed little with the exception of a spike

over 125 mg/L in 1991 . There is an increasing trend in samples from piezometer C767, increasing

from about 25 mg/L in 1989 to 75 mg/L in 1991. Since 1991, the chloride concentrations in samples

from C767 have remained about 75 mg/L. The chloride concentrations for samples from C766 have

shown little change since 1987 and remain between 20 and 30 mg/L, similar to ash-lagoon chloride

concentrations. The lag time for the boron concentration to increase when compared to chloride is

expected because boron moves slower through soil than an element like chloride. The higher boron

concentrations in samples from C767 than in samples from the other two piezometers are much

closer to the boron concentrations in the Polishing Pond.

The total calculated seepage from the ash lagoon was determined to be 1.51 Us. This is an

increase over the 1991 calculated value of 1.267 Us.

The increase can mostly be attributed to the increase in calculated seepage rates for Ash Lagoon

No. 1 from 0.245 L/s in 1991 to 0.417 L/s in 1992. The piezometric levels in the new piezometers
25

installed on the west side of Ash Lagoon No. 1 closely matched levels in other piezometers on the

west side of the ash lagoons and these levels did not affect calculations. However, the new

piezometers on the east side of Ash Lagoon No. 1 did indicate large increases in piezometric levels

from background values and when these levels were added to the calculation, the calculated seepage rates increased. The piezometers on the east side of Ash Lagoon No. 1 provided data in an

area where there was no previous information. Calculated liner permeabilities for the ash lagoons

have remained about 1 0"^ cm/sec.

The calculated total seepage from the ash lagoons is well below the seepage limits proposed in 1 979

by the International Poplar River Water Quality Board of the International Joint Commission.

3.3.3.2 Montana

Samples for water-quality analysis were collected from Montana monitoring wells 5-11, 15, 16, 19,

23, and 24 in 1992. Graphs of total dissolved solids for selected wells are shown in Figure 3.12.

200

Jan-79 Jan-81 Jan-83 Jan-85 Jan-87 Jan-89 Jan-91 Jan-93 Jan-95

Date

Figure 3.12 Total Dissolved Solids in Samples from Montana Monitoring Wells.
26

3.4 Cookson Reservoir

3.4.1 Storage

On January 1, 1992, Cookson Reservoir storage was 23 500 dam'^--54 percent of the full-supply

volume. During the year, precipitation was below normal resulting in below normal inflows. The

1992 maximum, minimum, and period elevations and volumes are shown in Table 3.4. In addition to

runoff, reservoir levels were augmented by ground-water pumpage. Wells in the abandoned west

block mine site supplied 5 225 dam"^ to Girard Creek. Approximately 70 percent of this flow volume

reached Cookson Reservoir. Wells in the Soil Salinity Project supplied 942 dam^^ directly to the

reservoir.

Table 3.4 Cookson Reservoir Storage Statistics for 1 992.

Date
27

_j 756 ^ 755

LlJ _l 754 ^ 753 > 751 ^

750

in 749 ^

748 ^

747 Z 746 2

745 O 744 ^

743

y 742 ^ 741 T 1 1 1 1 1 1 1 1 I f

Full Supply Level

missing data \

'Minimum Desired Operating Level

'Unusable Storage Level

MEAN DAILY WATER LEVEL FOR 1 992

MEDIAN OF MONTHLY MEAN ELEVATION FOR 1 981 -1 991

56500
28

3.5 Air Quality

3.5.1 Saskatchewan Environment and Resource Management

Ambient sulphur dioxide (SO2) monitoring was discontinued on March 30, 1 992. During the 3-month

period of 1992, ambient sulphur dioxide monitoring recorded no violations of Saskatchewan

Environment and Resource Management's hourly and 24-hour average standards of 0.17 and 0.06

parts per million (ppm), respectively. The highest recorded hourly value of 0.082 ppm SO2 was

recorded on March 27th at 13:00 hours, as compared to 0.137 ppm SO2 recorded in September

1 991 . The highest 24-hour average reading of 0.011 ppm occurred on March 27th as compared with

1991's highest average reading of 0.11 ppm. There was no downtime for the monitor during the 3-

month period.

The High-Volume Sampler was also discontinued on March 30, 1992. Suspended particulate

concentrations obtained from the monitor at the same site for the 3-month period did not exceed

Saskatchewan Environment and Resource Management's 24-hour average standard of 120

micrograms per cubic metre (ng/m^) per 24 hours as compared to the two occasions in 1991 in

September and October at 162.2 ^ig/m^, and 197.7 ^ig/m^ respectively. The annual geometric mean

was not calculated for 1992 and there was no downtime for the 3-month period as compared to 3.3

percent downtime for 1991

.

3.5.2 SaskPower Corporation

SaskPower Corporation's (SPC) ambient SO2 monitoring for 1992 recorded no violations of

Saskatchewan Environment and Resource Management's hourly and 24-hour average standards. The highest recorded hourly value of 0.067 ppm SO2 was recorded on October 9, 1992 at 11:00

hours.
29

Total suspended particulate concentrations for 1992 obtained from SPC's monitor exceeded

Saskatchewan's 24-hour standard of 120 ng/m^on three separate occasions: April 12th (246.4

M-g/m^), April 30th (318.6 ^ig/m^), and May 8 (363.6 \ig/m^). In all cases, the prevailing wind direction

eliminated the power station as a possible influence. The geometric mean for the high-volume air

sampler for 1 992 was 23.8 ^ig/m^.

3.6 Quality Control

3.6.1 Streamflow

To test the quality of streamflow calculations made by the U.S. Geological Survey (USGS) and

Environment Canada (EC), similar measurements were made on the East Poplar River at the

International Boundary on June 17, 1992 by personnel from both agencies. The discharges shown

in Table 3.5 agree within measurement error

Table 3.5 Streamflow Measurement Results for June 17, 1992.

Agency
30

Sets of triplicate samples were split from U.S. Geological Survey sampling chums and submitted to

tfie respective agency laboratories for analyses. Field procedures were identical to those used since

1986.

Most parameters showed acceptable reproducibility within and between sets of triplicates. Only the

variables for which corrective action should be considered are discussed here.

Field temperature results showed an unacceptable level of inter-agency variability with values

ranging from 16.5 °C to 18.0 °C. Dissoived-oxygen concentrations ranged from 10.0 to 11.2 mg/L

Between-triplicate results were not comparable for ortho phosphorus, total ammonia, chloride, total

barium, total vanadium, and dissolved iron.

For TDS, dissolved iron, dissolved boron, silica, total chromium and color, one set of results was

noticeably high compared to the other reported sets. Similariy one of the reported triplicate data

sets was low for lab pH.

Since most of the metals were present in the samples at concentrations near or below analytical

detection limits, a satisfactory evaluation of data comparability for these constituents is not possible.
31

4.0 REFERENCES CITED

Integrated Environments Limited, 1991 , The use of the TYDAC SPANS GIS in the assessment and

review of pesticide residues detected in surface waters of the Prairie Provinces and the Northwest

Territories. (Prepared for Environment Canada, Inland Waters Directorate, Western and Northern

Region, Water Quality Branch, Regina, Saskatchewan.) 138 p.

Lang, T.-A., and Jones, K., 1988, A comparison of the meteorological conditions during the droughts

of the 1930's and the 1980's for the Prairie Provinces. Environment Canada, Atmospheric

Environment Service, Regina. Report No. CSS-R89-01 (A publication of the Canadian Climate

Program.) 50 p.

ANNEX 1

POPLAR RIVER

COOPERATIVE MONITORING ARRANGEMENT

CANADA-UNITED STATES

A1-1
September 23, 1980

POPLAR RIVER COOPERATIVE MONITORING ARRANGEMENT

I. PURPOSE

This Arrangement will provide for the exchange of data collected as described in the attached

Technical Monitoring Schedules in water quality, water quantity and air quality monitoring programs

being conducted in Canada and the United States at or near the International Boundary in response

to SaskPower development. This Arrangement will also provide for the dissemination of the data in each country and will assure its comparability and assist in its technical interpretation. The Arrangement will replace and expand upon the quarterly information exchange program

instituted between Canada and the United States in 1976.

II. PARTICIPATING GOVERNMENTS

Governments and government agencies participating in the Arrangement are: Government of Canada: Environment Canada

Government of the Province of Saskatchewan:

Saskatchewan Environment and Public Safety (now Saskatchewan

Environment and Resource Management)

Government of the United States of America: U.S Geological Survey

Government of the State of Montana: Executive Office

III. POPLAR RIVER MONITORING COMMITTEE: TERMS OF REFERENCE

A binational committee called the Poplar River Bilateral Monitoring Committee will be established to carry out responsibilities assigned to it under this Arrangement. The Committee will operate in accordance with the following tenms of reference:

A. Membership

The Committee will be composed of four representatives, one from each of the participating Governments. It will be jointly chaired by the Govemment of Canada and the Government of the United States. There will be a Canadian Section and a United States Section. The participating Governments will notify each other of any changes in membership on the Committee. Cochairpersons may by mutual agreement invite agency technical experts to participate in the work of the Committee.

The Governor of the State of Montana may also appoint a chief elective official of local govemment

to participate as an ex-officio member of the Committee in its technical deliberations. The

Saskatchewan Minister of the Environment may also appoint a similar local representative.

B. Functions of the Committee

The role of the Committee will be to fulfill the purpose of the Arrangement by ensuring the exchange

of monitored data in accordance with the attached Technical Monitoring Schedules, and its collation and technical interpretation in reports to Governments on implementation of the Arrangement. In addition, the Committee will review the existing monitoring systems to ensure their adequacy and

A1-2
may recommend to the Canadian and United States Govemments any modifications to improve the Technical Monitoring Schedules.

1. Information Exchange

Each Co-chairperson will be responsible for transmitting to his counterpart Co-chairperson on a

regular, and not less than quarterly basis, the data provided by the cooperative monitoring agencies

in accordance with the Technical Monitoring Schedules.

2. Reports

(a) The Committee will prepare a joint Annual Report to the participating governments,

and may at any time prepare joint Special Reports.

(b) Annual Reports will

i) summarize the main activities of the Committee in the year under Report and the data which has been exchanged under the Arrangement;

ii) draw to the attention of the participating govemments any definitive changes in the monitored parameters, based on collation and technical interpretation of exchanged

data (i.e. the utilization of summary, statistical and other appropriate techniques);

iii) draw to the attention of the participating govemments any recommendations

regarding the adequacy or redundancy of any scheduled monitoring operations and

any proposals regarding modifications to the Technical Monitoring Schedules,

based on a continuing review of the monitoring programs including analytical

methods to ensure their comparability.

(c) Special Reports may, at any time, draw to the attention of participating governments

definitive changes in monitored parameters which may require immediate attention.

(d) Preparation of Reports

Reports will be prepared following consultation with all committee members and will be signed by all Committee members. Reports will be separately fon^^arded by the Committee Co-chairmen to the participating governments. All annual and special

reports will be so distributed.

3. Activities of Canadian and United States Sections

The Canadian and United States sections will be separately responsible for:

(a) dissemination of information within their respective countries, and the arrangement

of any discussion required with local elected officials;

(b) verification that monitoring operations are being carried out in accordance with the Technical Monitoring Schedules by cooperating monitoring agencies;

(c) receipt and collation of monitored data generated by the cooperating agencies in their respective countries as specified in the Technical Monitoring Schedules;

(d) if necessary, drawing to the attention of the appropriate government in their respective countries any failure to comply with a scheduled monitoring function on

the part of any cooperating agency under the jurisdiction of that government, and

requesting that appropriate corrective action be taken.

A1-3
IV. PROVISION OF DATA

In order to ensure that the Committee is able to carry out the terms of this Arrangement, the

participating govemments will use their best efforts to have cooperating monitoring agencies, in their respective jurisdictions provide on an ongoing basis all scheduled monitored data for which they are

responsible.

V. TERMS OF THE ARRANGEMENT

The Arrangement will be effective for an initial term of five years and may be amended by agreement

of the participating govemments. It will be subject to review at the end of the initial term and will be

renewed thereafter for as long as it is required by the participating govemments.

A1-4
ANNEX 2

POPLAR RIVER

COOPERATIVE MONITORING ARRANGEMENT

TECHNICAL MONITORING SCHEDULES

1993

CANADA-UNITED STATES

A2-1
TABLE OF CONTENTS

PREAMBLE A2-3

CANADA

STREAMFLOW MONITORING A2-5

SURFACE-WATER QUALITY MONITORING A2-7

GROUND-WATER QUALITY MONITORING A2-11 GROUND-WATER PIEZOMETER TO MONITOR

POTENTIAL DRAWDOWN DUE TO COAL SEAM DEWATERING A2-13

GROUND-WATER PIEZOMETER LEVEL MONITORING

- ASH LAGOON AREA

SCHEDULE A - PIEZOMETER IN TILL A2-15

GROUND-WATER PIEZOMETER LEVEL MONITORING

- ASH LAGOON AREA AND INTERNATIONAL BOUNDARY AREA

SCHEDULE B - PIEZOMETER IN EMPRESS GRAVEL A2-17

AMBIENT AIR QUALITY MONITORING A2-19

UNITED STATES

STREAMFLOW MONITORING A2-22 SURFACE-WATER QUALITY MONITORING A2-24

GROUND-WATER QUALITY MONITORING A2-26

GROUND-WATER LEVELS TO MONITOR POTENTIAL

DRAWDOWN DUE TO COAL SEAM DEWATERING A2-28

A2-2
PREAMBLE

The Technical Monitoring Schedule lists those water quantity, water quality, and air quality

monitoring locations and parameters which form the basis for information exchange and reporting to Govemments. The structure of the Committee responsible for ensuring the exchange takes place is described in the Poplar River Cooperative Monitoring Arrangement.

The monitoring locations and parameters listed herein have been reviewed by the Poplar River

Bilateral Monitoring Committee and represent the basic technical information needed to identify any

definitive changes in water quantity, water quality, and air quality at the Intemational Boundary. The

Schedule was initially submitted to Governments for approval as an attachment to the 1981 report to Govemments. Changes in the sampling locations and parameters may be made by Governments

based on the recommendation of the Committee.

Significant additional information is being collected by agencies on both sides of the Intemational Boundary, primarily for project management or basin-wide baseline data purposes. This additional information is usually available upon request from the collecting agency and forms part of the pool of technical information which may be drawn upon by Governments for specific study purposes. Examples of additional information are data on water quantity water quality, ground water, and air quality collected at points in the Poplar River basin not of direct concern to the Committee. In addition, supplemental information on parameters such as vegetation, soils, fish, and waterfowl

populations and aquatic vegetation Is also being collected as part of routine or specific studies by

various agencies.

A2-3
POPLAR RIVER

COOPERATIVE MONITORING ARRANGEMENT

TECHNICAL MONITORING SCHEDULES

1993

CANADA

A2-4
STREAMFLOW MONITORING

Responsible Agency: Environment Canada

Daily mean discharge or levels and instantaneous monthly extremes as nomally published in surface water data publications.

No. on Map
5 10 15 Km

1

I

I

I I

I 5 10 Miles

HYDROMETRIC GAUGING STATIONS (CANADA)

A2-6
SURFACE-WATER QUALITY MONITORING

Sampling Locations

Responsible Agency: Saskatchewan Environment and Resource lUanagement
PARAMETERS

Responsible Agency: Saskatchewan Environment and Resource Management
PARAMETERS (Continued)

Responsible Agency: Environment Canada
A ENVIRONMENT SflSKATCMEWAN ENVIRONMENT CANADA A

SCALE

5 10 15 Km

SURFACE WATER QUAUTY MONITORING STATIONS (CANADA)

A2-10
GROUND-WATER QUALITY MONITORING

SAMPLING LOCATIONS

Responsible Agency: Saskatchewan Environment and Resource Management |
PARAMETERS

Responsible Agency: Saskatchewan Environment and Resource Management |
GROUND-WATER PIEZOMETERS TO MONITOR POTENTIAL DRAWDOWN

DUE TO COAL SEAM DEWATERING

Responsible Agency: Saskatchewan Environment and Resource Management
GROUNDWATER PIEZOMETERS TO MONITOR POTENTIAL DRAWDOWN DUE TO COAL SEAM DEWATERING

A2-14
GROUND-WATER PIEZOMETER LEVEL MONITORING

Schedule A - Piezometers in Till ASH LAGOON AREA

Responsible Agency: Saskatchewan Environment and Resource Management |
T.I

LEGEND:

R.27

n SINGLE PIEZOMETER IN TILL a NESTED PIEZOMETER IN TILL 5 SITE NUMBER

Lagoor

24 Ash

Lagoon

lira] R[g

C653A|

15[n]

C534 7 &

C654

CANADA

A

SCALE

"i ^

500 1000 METBES

0.5 1.0 MILE

U.S.A. PIEZOMETER INSTALLATION SITES-SCHEDULE "A" PIEZOMETERS IN TILL

A2-16
GROUND-WATER PIEZOMETER LEVEL MONITORING

ASH LAGOON AREA AND INTERNATIONAL BOUNDARY AREA

Schedule B - Piezometers in Empress Gravel

Responsible Agency: Saskatchewan Environment and Resource Management
r

T.I

R.27

LEGEND:

3 PIEZOMETERS IN EMPRESS GRAVEL A PIEZOMETERS IN HART SEAM 5 SITE NUMBER ASCALE

^J ^

500 1000 METRES

U.S.A. PIEZOMETER INSTALLATION SITES-SCHEDULE "B" PIEZOMETERS IN EMPRESS GRAVEL

A2-18
AMBIENT AIR QUALITY MONITORING

Responsible Agency: Saskatchewan Environment and Resource Management J
LEGEND:

AMBIENT AIR QUAUTY MONITORING (CANADA)

A2-20
POPLAR RIVER

COOPERATIVE MONITORING ARRANGEMENT

TECHNICAL MONITORING SCHEDULES

1993

UNITED STATES

A2-21
STREAMFLOW MONITORING

Responsible Agency: U.S. Geological Survey
HYDROMETRIC GAUGING STATIONS (UNITED STATES)

A2-23
SURFACE-WATER QUALITY MONITORING
5 10 15 Km

SURFACE WATER QUAUTY MONITORING STATIONS (UNITED STATES)

A2-25
GROUND-WATER QUALITY MONITORING

Station Locations

Responsible Agency: Montana Bureau of Mines and Geology
5 10 15 Kr

GROUNDWATER QUAUTY MONITORING (UNITED STATES)

A2-27
GROUND-WATER LEVELS TO MONITOR POTENTIAL

DRAWDOWN DUE TO COAL SEAM DEWATERING

Responsible Agency: Montana Bureau of Mines and Geology
"^

10 Miles GROUNDWATER PIEZOMETERS TO MONITOR POTENTIAL DRAWDOWN DUE TO COAL SEAM DEWATERING

A2-29

ANNEX 3

RECOMMENDED FLOW APPORTIONMENT

IN THE POPLAR RIVER BASIN

BY THE INTERNATIONAL SOURIS-RED RIVERS ENGINEERING BOARD,

POPLAR RIVER TASK FORCE (1976)

A3-1
*RECOMMENDED FLOW APPORTIONMENT

IN THE POPLAR RIVER BASIN

The aggregate natural flow of all streams and tributaries in the Poplar River Basin crossing the

International Boundary shall be divided equally between Canada and the United States subject to the following conditions:

1. The total natural flow of the West Fork Poplar River and all its tributaries crossing the

International Boundary shall be divided equally between Canada and the United States but the flow at the International Boundary In each tributary shall not be depleted by more than 60

percent of its natural flow.

2. The total natural flow of all remaining streams and tributaries in the Poplar River Basin

crossing the International Boundary shall be divided equally between Canada and the United

States. Specific conditions of this division are as follows;

(a) Canada shall deliver to the United States a minimum of 60 percent of the natural flow of the Middle Fork Poplar River at the International Boundary as determined below the confluence of Goose Creek and Middle Fork.

(b) The delivery of water from Canada to the United States on the East Poplar River shall be determined on or about the first day of June each year as follows:

(i) When the total natural flow of the Middle Fork Poplar River, as detemiined below

the confluence of Goose Creek, during the immediately preceding March 1st to May 31st period does not exceed 4,690 cubic decameters (3,800 acre-feet), then a continuous minimum flow of 0.028 cubic metres per second (1 .0 cubic feet per second) shall be delivered to the United States on the East Poplar River at the

International Boundary throughout the succeeding 12 month period commencing

June 1st. In addition, a volume of 370 cubic decameters (300 acre-feet) shall be

delivered to the United States upon demand at any time during the 1 2 month period

commencing June 1st.

(ii) When the total natural flow of the Middle Fork Poplar River, as determined below

the confluence of Goose Creek, during the immediately preceding March 1st to May 31 st period Is greater than 4,690 cubic decameters (3,800 acre-feet), but does

not exceed 9,250 cubic decameters (7,500 acre-feet), then a continuous minimum

flow of 0.057 cubic metres per second (2.0 cubic feet per second) shall be

delivered to the United States on the East Poplar River at the International Boundary during the succeeding period June 1st through August 31st. A minimum

delivery of 0.028 cubic metres per second (1.0 cubic feet per second) shall then be

maintained from September 1st through to May 31st of the following year In addition, a volume of 617 cubic decameters (500 acre-feet) shall be delivered to the United States upon demand at any time during the 12-month period

commencing June 1st.

(iii) When the total natural flow of the Middle Fork Poplar River, as detennined below

the confluence of Goose Creek, during the immediately preceding March 1st to May 31 st period is greater than 9,250 cubic decameters (7,500 ace-feet), but does

Canada-United States, 1976, Joint studies for flow apportionment. Poplar River Basin,

Montana-Saskatchewan: Main Report, International Souris-Red Rivers Board, Poplar

River Task Force, 43 pp. A3-2
not exceed 14,800 cubic decameters (12,000 acre-feet), then a continuous

minimum flow of 0.085 cubic metres per second (3.0 cubic feet per second) shall then be delivered to the United States on the East Poplar River at the International Boundary during the succeeding period June 1st through August 31st. A minimum

delivery of 0.057 cubic metres per second (2.0 cubic feet per second) shall then be

maintained from September 1st through to May 31st of the following year In addition, a volume of 617 cubic decameters (500 acre-feet) shall be delivered to the United States upon demand at any time during the 12-month period

commencing June 1st.

(iv) When the total natural flow of the Middle Fork Poplar, as determined below the confluence of Goose Creek, during the immediately preceding March 1st to May

31st period exceeds 14,800 cubic decameters (12,000 acre-feet) then a

continuous minimum flow of 0.085 cubic metres per second (3.0 cubic feet per second) shall be delivered to the United States on the East Poplar River at the

International Boundary during the succeeding period June 1st through to August

31st. A minimum delivery of 0.057 cubic metres per second (2.0 cubic feet per second) shall then be maintained from September 1st through to May 31st of the

following year In addition, a volume of 1,230 cubic decameters (1,000 acre-feet)

shall be delivered to the United States upon demand at any time during the 12- month period commencing June 1st. (c) The natural flow at the International Boundary in each of the remaining individual

tributaries shall not be depleted by more than 60 percent of its natural flow. The natural flow and division periods for apportionment purposes shall be determined, unless

othenft^ise specified, for periods of time commensurate with the uses and requirements of both

countries.

A3-3

ANNEX 4

METRIC CONVERSIONS

A4-1