Powder/Tongue River Basin Water Plan
Technical Memoranda

SUBJECT:	Appendix M Available Surface Water Determination
PREPARED BY:	HKM Engineering Inc.
DATE:	February 2002

INTRODUCTION

Spreadsheet water accounting models have been developed for the following six primary subbasins in the Powder/Tongue River Basin planning area to represent streamflows under current levels of development.

1. Little Bighorn
2. Tongue River
3. Clear Creek
4. Crazy Woman Creek
5. Powder River
6. Little Powder River

The purpose of the current task is to analyze the results of the spreadsheet model runs to determine where water shortages currently exist and to determine the location, quantity, and timing of available flows for future development.

WATER SHORT AREAS

HKM reviewed the results of the water availability modeling runs to make a determination of where water shortages occur under existing conditions. The results of the modeling were further reviewed by identifying those ditches that have experienced relatively low diversions historically in comparison to other ditches. As a further crosscheck, the initial determinations of water short areas were reviewed with the SEO Division 2 Superintendent for reasonableness. It is recognized that almost every area of the planning area can be considered water short during severe dry years such as were experienced during the summer of 2001. The purpose of this investigation is to identify those areas that experience relatively high shortages in comparison to other areas in the Basin. The areas listed in Table 1 were identified as being water short in a typical year.

Table 1 Water Short Areas During Normal Hydrologic Conditions
River Basin	Stream
Little Bighorn River	Twin Cr. East Pass Cr.
Tongue River	Columbus Cr. Smith Cr. Rapid Cr. Little Goose Cr. Soldier Cr. Wolf Cr. Little Tongue R.
Clear Creek	Little Piney Cr. Rock Cr. Johnson Cr. French Cr. Clear Cr.
Crazy Woman Creek	N. Fk. Crazy Woman Cr. Muddy Cr. (trib. of N.Fk. Crazy Woman Cr.) Middle Fk. Crazy Woman Cr.
Powder River	N. Fk. Powder R. Buffalo Cr. Middle Fk. Powder
Little Powder River	Little Powder River

AVAILABLE FLOW

Each basin model is divided into a number of reaches, each composed of several nodes, or water balance points. Reaches are typically defined by gages or confluences, and represent tributary basins or subsections of the mainstem. A Reach Outflow worksheet is provided in each model summarizing the monthly flow at the downstream end of each reach. The information provided in these summaries is the basis for this analysis.

While simulated flow at the reach terminus indicates the estimated amount of water physically present, it does not fully reflect availability. Downstream demands relying on the water physically available at any given location must first be accounted for. These downstream demands fall into three general categories:

1. Existing irrigation, or municipal diversions
2. Instream flow constraints
3. Compact constraints

To determine how much of the physical supply is actually available in excess of existing demands, "available flow" at each reach terminus is defined as the minimum of the physically available flow at that point, and the "available flow" at all downstream reaches. Thus available flow must be defined first at the most downstream point, with upstream availability calculated in stream order. These calculations are made on a monthly basis, and annual water availability is computed as the sum of monthly values. Note that calculating annual availability in this way yields a different result than applying the same logic to annual flows for each reach. The summation of monthly values is more accurate, reflecting constraints of downstream use on a monthly basis.

Instream Flow Constraints

Instream flow rights exert a demand on the river but do not affect physical supply, because the water is not removed from the stream. Sufficient flow must be bypassed through upstream reaches to satisfy downstream instream flow requirements. The available flow for reaches located upstream from permitted instream flows are determined as the minimum of physical flow at that point, and available flow in excess of existing diversion demands less the instream flow requirement at the downstream reach.

The six permitted instream flow rights in the planning area are described in the Environmental Water Use memorandum (HKM, 2002). With only one exception, all of the instream flow rights are located above the most upstream reach explicitly simulated in the model. The available flow for future development reported herein, therefore, is downstream from most of these instream flow constraints. The exception is a 9.86-mile long reach of the Middle Fork Powder River with a 1987 priority instream flow requirement of 12 to 25 cfs. The available flow in Reach 2 of the Powder River sub-basin was calculated taking this instream flow demand into consideration.

The reach by reach results of the monthly available flow determination, accounting for the instream flow constraints, are provided in Tables 2 through 19 for each of the six subbasins and for each of the three hydrologic conditions (wet, normal, and dry years). The total annual available flow is summarized in Table 20 for each subbasin and hydrologic condition.

Table 20 Total Annual Available Flow
Subbasin	Hydrologic Condition
	Wet Years	Normal Years	Dry Years
Little Bighorn River	152,000	113,000	81,000
Tongue River	473,000	326,000	218,000
Clear Creek	213,000	124,000	80,000
Crazy Woman Creek	69,000	32,000	16,000
Powder River	547,000	324,000	194,000
Little Powder River	48,000	12,000	3,000

The yield potential of each of these basins is limited by the dry year conditions. Further, the timing of these available flows does not necessarily match the timing of the demand for this water. For example of the 218,000 acre feet of available flow from the Tongue River during a typical dry year, 65 percent of this occurs during the spring runoff months of March through June. Reservoir storage would be required to store this excess flow to satisfy demands throughout the year. The available flow presented in Table 20 does not include the constraints of the Yellowstone River Compact. This will be discussed in the next section.

Compact Constraints

A determination of the amount of water available to Wyoming for future development is not complete without an evaluation of the constraints imposed by interstate compacts. The Yellowstone River Compact of 1950 governs the allocation of the waters in the Powder River and Tongue River between the States of Montana and Wyoming.

The following is a brief summary of the rules for dividing the waters according to the Yellowstone River Compact (SEO, 1982):

1. existing rights as of January 1, 1950 maintain their status quo;
2. no water may be diverted from the Yellowstone River Basin for use in another River Basin without consent from all states;
3. existing and future domestic and stock water uses including stock water reservoirs up to a capacity of 20 acre-feet are exempted from provisions of the Compact.

   The unappropriated or unused total divertible flow of each tributary after needs for supplemental supply for existing rights are met, is allocated to Wyoming and Montana on a percentage basis

   Nothing contained in the Compact is to be construed to adversely affect any rights to the use of the waters of the Yellowstone River by or for Indians, Indian tribes, and their reservations.

The methodology used in the current study to evaluate water availability under the Yellowstone River Compact was coordinated through the Wyoming State Engineers Office and relies heavily on previous work performed by others on behalf of each of the two States (Tavelli, October 2001). A more detailed, "from the ground up" evaluation is beyond the scope of the current planning effort. The methodology employed provides estimates of Wyoming's allocation under each of the three hydrologic conditions (wet, normal, and dry years).

'

Table 2 Available Flow for Little Bighorn Basin (Acre-Feet) - Wet Year Hydrologic Conditions
Reach	Reach Name	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Annual
1	East Pass Cr below USGS gage 06289800	549	484	684	1,035	3,727	4,598	1,411	517	721	710	600	210	15,555
2	East Pass Cr below USGS gage 06289820	568	496	690	1,035	3,741	4,636	1,458	573	788	760	638	549	15,931
3	Elkhorn Creek below USGS gage 06288975	89	81	92	136	711	1,115	315	147	150	118	102	95	3,153
4	Red Canyon Creek below USGS gage 06289100	46	37	66	346	1,001	421	105	48	44	60	52	42	2,268

'

Table 3 Available Flow for Little Bighorn Basin (Acre-Feet) - Normal Year Hydrologic Conditions
Reach	Reach Name	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Annual
1	East Pass Cr below USGS gage 06289800	528	542	635	982	2,882	2,855	883	494	512	596	562	544	12,016
2	East Pass Cr below USGS gage 06289820	549	556	643	988	2,906	2,902	937	556	589	654	605	575	12,461
3	Elkhorn Creek below USGS gage 06288975	86	75	88	137	464	592	174	124	114	116	101	92	2,164
4	Red Canyon Creek below USGS gage 06289100	29	24	43	213	544	238	61	29	28	40	35	28	1,313

'

Table 4 Available Flow for Little Bighorn Basin (Acre-Feet) - Dry Year Hydrologic Conditions
Reach	Reach Name	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Annual
1	East Pass Cr below USGS gage 06289800	506	458	592	790	1,407	1,317	673	398	475	620	578	551	8,364
2	East Pass Cr below USGS gage 06289820	527	472	600	804	1,455	1,387	743	470	565	688	628	586	8,926
3	Elkhorn Creek below USGS gage 06288975	81	70	83	141	317	246	133	109	91	104	97	90	1,562
4	Red Canyon Creek below USGS gage 06289100	23	17	24	125	258	101	32	20	23	29	28	22	702

Table 5 Available Flow for Tongue River Basin (Acre-Feet) - Wet Year Hydrologic Conditions
Reach	Reach Name	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Annual
1	Tongue River above Little Tongue River	3,493	3,099	4,101	5,652	34,863	69,125	25,201	8,354	5,454	5,369	4,132	3,715	172,557
2	Little Tongue River	132	109	151	334	4,235	7,620	1,320	56	0	238	164	143	14,502
3	Tongue River above Wolf Creek	3,826	3,343	4,325	5,986	39,098	76,744	26,521	8,410	5,454	6,123	4,689	4,156	188,675
4	Wolf Creek	507	395	456	736	7,343	12,285	2,000	0	10	1,014	765	630	26,141
5	Tongue River above Goose Creek	4,443	3,889	4,866	6,723	46,441	89,029	28,521	8,410	5,464	7,481	5,891	4,915	216,074
6	Big Goose Creek above Rapid Creek	904	1,286	2,907	3,434	20,500	45,977	15,058	2,911	3,258	1,898	1,341	1,169	100,643
7	Rapid Creek	69	73	140	48	622	1,269	914	0	0	113	91	79	3,418
8	Big Goose Creek above Beaver Creek	1,124	1,461	3,103	3,483	21,123	47,246	15,972	2,911	3,258	2,218	1,725	1,471	105,095
9	Beaver Creek	93	60	52	73	492	715	180	88	71	220	186	142	2,373
10	Big Goose Creek above Little Goose Creek	1,400	1,633	3,209	3,561	21,649	48,030	16,152	2,998	3,329	2,438	2,037	1,704	108,141
11	Little Goose Creek	2,224	2,093	3,152	3,297	17,881	21,368	4,782	1,962	3,047	3,462	2,966	2,478	68,712
12	Goose Creek above Soldier Creek	3,931	3,983	6,542	7,735	41,796	70,136	20,934	4,960	6,376	5,901	5,002	4,182	181,477
13	Soldier Creek	975	690	596	535	1,360	1,604	490	436	579	1,013	928	806	10,013
14	Goose Creek below Soldier Creek	4,906	4,767	7,306	8,477	44,499	75,198	22,253	5,480	7,142	6,914	6,062	4,988	197,990
15	Goose Creek above Tongue River	4,906	5,011	9,233	10,526	51,560	78,270	24,483	5,480	7,566	6,914	6,182	4,988	215,479
16	Tongue River above Prairie Dog Creek	9,349	8,940	14,121	17,249	98,002	167,299	53,003	14,251	13,030	14,395	12,185	9,903	431,727
17	Prairie Dog Creek above USGS gage 06306250	991	1,816	5,423	3,027	8,112	3,531	2,223	2,239	2,303	2,132	1,815	1,449	35,063
18	Prairie Dog Creek above Tongue River	991	1,909	6,853	3,768	9,419	3,687	2,475	2,476	2,513	2,132	1,851	1,449	39,522
19	Tongue River above State Line	10,340	10,940	21,038	21,378	108,313	171,233	55,478	16,727	15,543	16,527	14,165	11,352	473,035

Table 6 Available Flow for Tongue River Basin (Acre-Feet) - Normal Year Hydrologic Conditions
Reach	Reach Name	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Annual
1	Tongue River above Little Tongue River	4,097	3,785	4,287	6,797	31,196	40,228	14,135	5,834	4,768	5,298	4,087	3,729	128,239
2	Little Tongue River	153	146	167	389	2,860	3,579	524	0	0	224	162	140	8,344
3	Tongue River above Wolf Creek	4,440	4,054	4,518	7,186	34,055	43,806	14,659	5,834	4,768	6,046	4,654	4,166	138,186
4	Wolf Creek	549	469	459	779	4,696	6,156	603	0	66	1,000	763	615	16,155
5	Tongue River above Goose Creek	5,203	4,663	5,051	7,965	38,751	49,962	15,262	5,834	5,061	7,484	5,868	5,113	156,217
6	Big Goose Creek above Rapid Creek	1,167	1,996	2,534	3,506	12,104	24,197	4,773	2,016	1,844	1,864	1,365	1,191	58,558
7	Rapid Creek	71	105	122	0	0	1,735	104	0	0	99	90	76	2,402
8	Big Goose Creek above Beaver Creek	1,383	2,196	2,705	3,506	12,104	25,933	4,877	2,016	2,077	2,219	1,758	1,491	62,264
9	Beaver Creek	98	71	51	62	292	386	117	74	132	247	207	154	1,890
10	Big Goose Creek above Little Goose Creek	1,663	2,378	2,808	3,568	12,431	26,426	5,152	2,090	2,604	2,466	2,129	1,877	65,590
11	Little Goose Creek	2,131	2,441	2,613	3,370	9,008	9,619	1,226	1,802	2,081	3,388	2,962	2,569	43,210
12	Goose Creek above Soldier Creek	3,957	4,959	5,472	8,222	22,407	36,483	8,086	3,892	5,273	5,854	5,091	4,446	114,140
13	Soldier Creek	679	548	475	507	905	901	600	348	774	960	884	786	8,366
14	Goose Creek below Soldier Creek	4,729	5,627	6,080	8,953	24,129	38,824	8,919	4,325	6,185	6,832	6,107	5,341	126,069
15	Goose Creek above Tongue River	5,712	7,430	8,224	10,623	24,604	39,850	9,845	4,327	6,513	6,832	6,107	5,341	135,408
16	Tongue River above Prairie Dog Creek	10,970	12,129	13,293	18,588	63,356	89,813	25,107	10,161	11,574	14,317	12,091	10,471	291,870
17	Prairie Dog Creek above USGS gage 06306250	1,174	2,419	4,913	2,968	2,928	2,289	1,335	1,630	2,521	2,471	1,977	1,644	28,268
18	Prairie Dog Creek above Tongue River	1,418	3,193	6,645	3,535	3,000	2,364	1,511	1,713	2,727	2,471	1,977	1,644	32,198
19	Tongue River above State Line	12,437	15,372	19,950	22,686	66,751	92,276	27,317	11,874	14,461	16,788	14,097	12,116	326,123

Table 7 Available Flow for Tongue River Basin (Acre-Feet) - Dry Year Hydrologic Conditions
Reach	Reach Name	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Annual
1	Tongue River above Little Tongue River	3,004	2,653	3,226	7,848	31,008	19,377	5,581	3,057	2,722	4,730	3,749	3,259	90,215
2	Little Tongue River	107	90	113	353	2,579	1,392	0	0	0	193	143	122	5,092
3	Tongue River above Wolf Creek	3,111	2,773	3,408	8,201	33,587	20,768	5,581	3,057	2,722	5,505	4,368	3,381	96,462
4	Wolf Creek	394	313	348	606	4,271	2,173	0	0	26	969	747	503	10,350
5	Tongue River above Goose Creek	3,505	3,086	3,840	8,807	37,857	22,941	5,581	3,057	3,017	6,474	5,283	3,884	107,333
6	Big Goose Creek above Rapid Creek	1,019	1,132	2,622	2,573	13,498	9,327	84	0	0	1,631	1,265	1,154	34,305
7	Rapid Creek	64	64	123	0	0	584	0	0	0	74	87	76	1,073
8	Big Goose Creek above Beaver Creek	1,216	1,276	2,789	2,573	13,498	9,911	97	102	202	1,773	1,656	1,281	36,374
9	Beaver Creek	52	29	37	0	282	192	48	12	0	174	175	100	1,101
10	Big Goose Creek above Little Goose Creek	1,312	1,341	2,868	2,573	13,779	10,333	373	376	526	1,947	1,831	1,381	38,641
11	Little Goose Creek	1,661	1,581	2,723	1,357	6,347	1,038	887	932	1,042	2,661	2,468	1,789	24,485
12	Goose Creek above Soldier Creek	2,973	2,922	5,636	6,367	20,126	15,795	2,242	1,502	2,100	4,607	4,299	3,170	71,738
13	Soldier Creek	602	514	501	598	821	810	671	379	649	909	861	638	7,952
14	Goose Creek below Soldier Creek	3,575	3,436	6,277	7,133	21,677	17,157	2,912	1,880	2,749	5,517	5,160	3,808	81,280
15	Goose Creek above Tongue River	3,575	3,436	7,041	7,615	21,726	17,598	2,912	1,880	2,749	5,517	5,160	3,808	83,018
16	Tongue River above Prairie Dog Creek	7,080	6,522	10,881	16,422	59,584	40,540	8,494	4,938	5,765	11,990	10,443	7,692	190,351
17	Prairie Dog Creek above USGS gage 06306250	938	1,975	4,793	2,043	1,678	1,279	878	1,496	1,928	2,055	1,695	1,196	21,953
18	Prairie Dog Creek above Tongue River	938	1,975	5,366	2,208	1,696	1,335	878	1,496	1,928	2,055	1,695	1,196	22,765
19	Tongue River above State Line	8,018	8,497	16,247	19,902	61,280	43,982	10,638	6,433	7,775	14,045	12,138	8,888	217,843

Table 8 Available Flow for Clear Creek Basin (Acre-Feet) - Wet Year Hydrologic Conditions
Reach	Reach Name	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Annual
1	North Piney Creek	225	215	333	1,155	10,872	16,085	2,167	415	182	556	400	225	32,862
2	South Piney Creek	779	712	947	1,393	6,134	20,952	8,806	2,959	1,158	1,702	1,158	889	47,589
3	Piney Creek below North & South Piney Creeks	1,004	927	1,280	2,549	17,006	37,038	10,973	3,374	1,340	2,259	1,558	1,444	80,451
4	Piney Creek below USGS gage 06323000	1,004	927	1,280	2,549	17,006	37,038	10,973	3,374	1,762	2,259	1,558	1,444	80,873
5	Piney Creek below Lake DeSmet Intake Tunnel	1,655	1,142	2,336	3,204	17,006	37,038	12,311	4,386	1,852	2,655	2,529	1,150	87,264
6	Little Piney Creek above SEO gage	642	833	1,030	904	1,426	2,311	1,336	722	707	925	830	582	12,246
7	Little Piney Creek above Piney Creek	1,058	960	1,786	904	1,426	2,311	1,434	939	743	1,087	1,346	585	14,578
8	Piney Creek below Little Piney Creek	2,712	2,191	4,172	4,108	18,431	39,348	13,745	5,325	2,595	3,742	4,072	1,736	102,179
10	Piney Creek below Box Elder Creek	2,712	2,221	4,190	4,203	18,431	39,348	13,745	5,325	2,595	3,742	4,072	1,736	102,322
11	Piney Creek above Clear Creek	2,712	3,224	5,689	5,198	18,431	39,348	13,745	5,325	2,595	3,742	4,072	1,736	105,819
12	Rock Creek	524	815	1,408	1,274	8,173	12,220	2,799	769	615	1,008	863	330	30,798
13	Johnson Creek	48	50	83	38	326	456	0	0	0	122	134	45	1,304
14	Rock Creek below Johnson Creek	573	865	1,491	1,451	9,102	12,676	2,799	769	615	1,130	997	376	32,844
15	Rock Creek above Clear Creek	573	865	1,491	1,451	9,102	12,676	2,799	769	615	1,130	997	376	32,844
16	French Creek	73	53	57	55	1,135	1,981	1,672	182	0	118	141	55	5,523
17	Clear Creek above City of Buffalo	1,046	1,423	1,982	2,929	15,386	21,221	8,254	1,672	1,168	2,226	1,945	756	60,007
18	Clear Creek above French Creek	1,046	1,423	1,982	2,929	15,449	21,221	8,254	1,672	1,168	2,226	1,945	756	60,070
19	Clear Creek above Rock Creek	1,119	1,476	2,039	2,984	16,584	23,202	9,926	1,854	1,398	2,344	2,086	811	65,823
20	Clear Creek below Rock Creek	1,691	2,341	3,530	4,435	25,686	35,878	12,725	2,624	2,014	3,474	3,084	1,186	98,668
21	Clear Creek above Healy Reservoir	1,691	2,658	3,530	4,435	25,686	35,878	12,725	2,624	2,014	4,444	3,084	1,186	99,955
23	Clear Creek above Piney Creek	1,691	3,911	4,824	5,374	25,686	35,878	12,725	2,624	2,014	4,444	3,128	1,186	103,486
24	Clear Creek above Double Crossing	4,404	7,135	10,514	10,678	44,118	75,227	26,470	7,949	4,609	8,186	7,200	2,922	209,410
25	Clear Creek below Double Crossing	4,404	7,135	10,514	10,929	44,118	75,227	26,470	7,949	4,609	8,186	7,200	2,922	209,661
26	Clear Creek above USGS gage 06324000	4,404	7,135	10,514	10,929	44,118	75,227	26,470	7,949	4,609	8,186	7,200	2,922	209,661
27	Clear Creek above Powder River	4,440	7,568	11,728	10,929	44,118	75,227	27,431	8,047	4,609	8,186	7,345	2,922	212,547
28	Powder River above Clear Creek	7,589	11,731	30,400	20,315	102,759	87,040	26,344	8,276	4,655	16,458	11,810	6,250	333,625
29	Powder River above State Line	12,118	19,360	42,163	31,243	146,877	162,267	53,775	16,330	9,263	24,643	19,325	9,172	546,537

Table 9 Available Flow for Clear Creek Basin (Acre-Feet) - Normal Year Hydrologic Conditions
Reach	Reach Name	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Annual
1	North Piney Creek	171	173	282	891	5,910	5,342	714	217	197	427	316	188	14,829
2	South Piney Creek	472	422	578	788	3,263	10,730	3,104	1,680	1,235	1,036	741	525	24,574
3	Piney Creek below North & South Piney Creeks	642	595	861	1,678	9,173	16,073	3,818	1,897	1,432	1,463	1,057	713	39,403
4	Piney Creek below USGS gage 06323000	642	595	861	1,678	9,173	16,073	3,818	2,047	1,432	1,463	1,057	713	39,552
5	Piney Creek below Lake DeSmet Intake Tunnel	914	656	1,389	2,465	9,915	16,073	3,818	2,631	1,858	1,463	1,668	1,036	43,887
6	Little Piney Creek above SEO gage	549	707	950	954	904	828	652	584	718	744	722	580	8,892
7	Little Piney Creek above Piney Creek	781	781	1,533	1,339	904	828	652	750	931	744	1,139	842	11,224
8	Piney Creek below Little Piney Creek	1,823	1,524	2,971	3,804	10,819	16,901	4,470	3,504	3,595	3,045	3,091	2,080	57,629
10	Piney Creek below Box Elder Creek	1,851	1,543	2,979	3,926	10,819	16,901	4,470	3,504	3,595	3,045	3,150	2,126	57,910
11	Piney Creek above Clear Creek	2,483	2,956	5,419	4,932	10,819	16,901	4,470	3,504	3,595	3,823	4,018	2,659	65,579
12	Rock Creek	283	441	1,061	766	3,283	4,820	954	479	439	545	417	297	13,787
13	Johnson Creek	28	32	62	0	0	0	0	0	0	86	74	42	324
14	Rock Creek below Johnson Creek	311	474	1,123	1,203	3,283	4,820	954	479	514	631	491	339	14,623
15	Rock Creek above Clear Creek	311	474	1,123	1,203	3,283	4,820	954	479	514	631	491	339	14,623
16	French Creek	63	45	49	67	552	1,022	619	0	0	170	125	94	2,805
17	Clear Creek above City of Buffalo	457	526	1,090	2,159	6,836	11,079	3,063	1,339	1,501	1,115	757	563	30,483
18	Clear Creek above French Creek	457	526	1,090	2,261	6,836	11,079	3,063	1,339	1,501	1,115	757	563	30,586
19	Clear Creek above Rock Creek	520	571	1,138	2,329	7,388	12,101	3,682	1,339	1,614	1,285	882	656	33,504
20	Clear Creek below Rock Creek	831	1,044	2,262	3,532	10,670	16,921	4,636	1,818	2,127	1,916	1,373	996	48,127
21	Clear Creek above Healy Reservoir	831	1,044	2,262	3,532	10,670	16,921	4,636	1,818	2,127	1,916	1,373	996	48,127
23	Clear Creek above Piney Creek	1,197	2,062	4,148	4,253	10,670	16,921	4,636	1,818	2,127	2,638	1,933	1,364	53,768
24	Clear Creek above Double Crossing	3,680	5,128	9,624	9,332	21,489	33,822	9,106	5,322	5,723	6,461	5,951	4,023	119,660
25	Clear Creek below Double Crossing	3,680	5,673	9,946	9,798	21,489	33,822	9,106	5,322	5,723	6,461	5,951	4,023	120,994
26	Clear Creek above USGS gage 06324000	3,680	5,852	10,041	9,798	21,489	33,822	9,106	5,322	6,083	6,461	5,951	4,023	121,630
27	Clear Creek above Powder River	3,734	6,701	10,850	9,798	21,489	33,822	9,635	5,322	6,083	6,523	5,951	4,023	123,932
28	Powder River above Clear Creek	6,519	13,902	25,996	22,124	40,971	37,368	14,105	6,557	6,452	9,968	9,003	6,715	199,680
29	Powder River above State Line	10,319	20,648	36,869	31,922	62,461	71,190	23,837	11,879	12,535	16,672	14,954	10,739	324,023

Table 10 Available Flow for Clear Creek Basin (Acre-Feet) - Dry Year Hydrologic Conditions
Reach	Reach Name	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Annual
1	North Piney Creek	102	96	127	1,422	3,684	1,116	263	77	61	294	179	116	7,536
2	South Piney Creek	284	260	331	758	2,029	4,195	1,770	707	436	680	373	306	12,129
3	Piney Creek below North & South Piney Creeks	387	356	458	2,180	5,713	5,311	2,033	784	497	974	552	422	19,666
4	Piney Creek below USGS gage 06323000	387	356	458	2,180	5,713	5,311	2,871	1,073	1,094	974	552	422	21,391
5	Piney Creek below Lake DeSmet Intake Tunnel	1,168	464	548	2,517	5,713	5,311	3,138	1,668	1,621	974	1,305	1,262	25,688
6	Little Piney Creek above SEO gage	627	589	941	809	263	534	660	538	586	766	760	636	7,708
7	Little Piney Creek above Piney Creek	1,894	768	1,128	934	263	534	721	836	868	766	1,799	1,901	12,411
8	Piney Creek below Little Piney Creek	3,181	1,307	1,717	3,451	5,976	5,845	3,859	3,013	2,522	3,235	3,416	3,176	40,699
10	Piney Creek below Box Elder Creek	3,181	1,307	1,717	3,657	5,976	5,845	3,859	3,013	2,522	3,235	3,416	3,176	40,905
11	Piney Creek above Clear Creek	3,670	1,828	2,931	3,810	5,976	5,845	3,859	3,013	2,522	4,247	4,579	3,176	45,456
12	Rock Creek	315	485	904	173	2,269	617	0	0	0	409	379	342	5,890
13	Johnson Creek	28	30	47	0	0	0	0	0	0	59	60	39	263
14	Rock Creek below Johnson Creek	343	515	951	905	2,269	617	146	97	111	467	439	381	7,241
15	Rock Creek above Clear Creek	343	515	951	905	2,269	617	146	97	111	467	439	381	7,241
16	French Creek	66	47	44	0	410	161	240	0	0	180	138	90	1,376
17	Clear Creek above City of Buffalo	643	919	1,106	2,403	4,118	2,681	530	339	322	1,000	871	776	15,707
18	Clear Creek above French Creek	643	919	1,106	2,403	4,118	2,681	530	339	322	1,000	871	776	15,707
19	Clear Creek above Rock Creek	709	966	1,150	2,403	4,528	2,841	769	339	322	1,180	1,009	867	17,082
20	Clear Creek below Rock Creek	1,052	1,480	2,101	3,308	6,797	3,458	915	436	433	1,647	1,448	1,248	24,323
21	Clear Creek above Healy Reservoir	1,052	1,480	2,101	3,308	6,797	3,458	915	436	433	1,647	1,448	1,248	24,323
23	Clear Creek above Piney Creek	1,294	2,120	3,625	3,308	6,797	3,458	915	436	433	2,440	2,165	1,287	28,278
24	Clear Creek above Double Crossing	4,964	3,949	6,584	7,413	12,773	9,303	4,774	3,449	2,955	6,687	6,744	4,462	74,056
25	Clear Creek below Double Crossing	4,964	3,949	8,902	8,139	12,773	9,303	4,774	3,449	2,955	6,687	6,744	4,462	77,102
26	Clear Creek above USGS gage 06324000	4,964	3,949	8,956	8,554	12,773	9,400	4,774	3,449	3,482	6,687	6,744	4,462	78,194
27	Clear Creek above Powder River	4,964	3,949	9,016	8,554	12,773	10,282	4,774	3,698	3,482	7,125	7,038	4,462	80,118
28	Powder River above Clear Creek	6,602	9,561	18,787	13,486	20,647	10,304	5,594	3,013	2,122	8,145	8,998	5,803	113,062
29	Powder River above State Line	11,567	13,510	27,822	22,040	33,420	20,735	10,368	6,822	5,603	15,447	16,172	10,265	193,770

Table 11 Available Flow for Crazy Woman Creek Basin (Acre-Feet) - Wet Year Hydrologic Conditions
Reach	Reach Name	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Annual
1	Kelly Creek	10	8	8	98	679	731	180	95	20	17	13	11	1,870
2	Little North Fork Crazy Woman Creek	22	18	19	214	1,499	1,602	371	182	36	38	29	25	4,055
3	North Fork Crazy Woman Creek	79	57	69	761	7,592	10,292	1,619	714	143	141	98	87	21,650
4	N Fk Crazy Woman Cr bel. Kelly & Little N Fk	111	84	96	1,073	9,769	12,626	2,170	990	199	195	139	124	27,575
5	Muddy Creek	17	14	16	198	1,347	1,398	318	150	19	27	20	18	3,541
6	Billy Creek	10	9	12	137	443	401	93	77	16	12	10	10	1,230
7	N Fk Crazy Woman Cr bel. Muddy & Billy Cr	137	107	123	1,408	11,559	14,425	2,581	1,217	234	234	169	152	32,346
8	Middle Fork Crazy Woman Creek	75	60	82	885	5,421	6,630	1,386	865	177	108	79	75	15,842
9	Crazy Woman Cr above S Fk Crazy Woman Cr	213	167	205	2,293	16,980	21,055	3,967	2,082	411	342	248	227	48,189
10	Crazy Woman Cr above Trabing Bridge	213	167	205	2,705	16,980	21,055	3,967	2,082	411	342	248	227	48,600
11	Crazy Woman Cr above Upper Station	792	1,494	2,802	3,472	20,742	21,055	3,967	2,082	411	2,439	1,522	720	61,498

Table 12 Avaliable Flow for Crazy Woman Creek Basin (Acre-Feet) - Normal Year Hydrologic Conditions
Reach	Reach Name	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Annual
1	Kelly Creek	9	7	8	64	279	283	86	37	20	17	11	11	831
2	Little North Fork Crazy Woman Creek	21	15	17	136	598	587	160	65	32	39	26	25	1,720
3	North Fork Crazy Woman Creek	67	49	58	538	3,544	3,251	780	279	133	128	87	82	8,995
4	N Fk Crazy Woman Cr bel. Kelly & Little N Fk	97	71	83	739	4,421	4,120	1,025	380	185	184	124	117	11,546
5	Muddy Creek	16	12	14	125	511	470	87	26	0	28	18	18	1,325
6	Billy Creek	9	8	10	74	179	143	39	39	8	12	9	9	539
7	N Fk Crazy Woman Cr bel. Muddy & Billy Cr	122	91	107	937	5,111	4,734	1,151	445	193	224	151	144	13,410
8	Middle Fork Crazy Woman Creek	64	53	75	652	2,684	2,366	667	344	90	100	70	70	7,235
9	Crazy Woman Cr above S Fk Crazy Woman Cr	186	144	182	1,589	7,795	7,100	1,818	789	283	324	221	215	20,645
10	Crazy Woman Cr above Trabing Bridge	186	144	182	1,589	7,795	7,100	2,075	959	812	324	221	215	21,602
11	Crazy Woman Cr above Upper Station	656	1,679	2,626	3,560	7,795	7,100	2,075	1,016	812	1,321	1,184	786	30,610

Table 13 Available Flow for Crazy Woman Creek Basin (Acre-Feet) - Dry Year Hydrologic Conditions
Reach	Reach Name	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Annual
1	Kelly Creek	10	7	8	39	57	54	0	0	0	17	11	12	215
2	Little North Fork Crazy Woman Creek	24	16	19	79	121	99	0	0	0	38	24	27	446
3	North Fork Crazy Woman Creek	71	47	58	365	620	511	0	0	0	124	74	79	1,949
4	N Fk Crazy Woman Cr bel. Kelly & Little N Fk	105	71	84	483	798	663	0	0	0	179	109	118	2,610
5	Muddy Creek	19	14	17	68	104	33	0	0	0	30	19	20	325
6	Billy Creek	11	9	12	39	38	4	0	0	0	13	9	10	145
7	N Fk Crazy Woman Cr bel. Muddy & Billy Cr	135	94	114	590	941	700	0	0	0	222	137	148	3,080
8	Middle Fork Crazy Woman Creek	76	59	79	423	501	453	0	0	0	108	67	73	1,839
9	Crazy Woman Cr above S Fk Crazy Woman Cr	210	153	193	1,013	1,442	1,153	0	0	0	330	204	221	4,918
10	Crazy Woman Cr above Trabing Bridge	210	153	193	1,013	1,442	1,788	532	168	123	330	204	221	6,377
11	Crazy Woman Cr above Upper Station	836	1,031	1,904	2,113	3,540	2,361	532	168	123	1,022	1,135	754	15,520

Table 14 Available Flow for Powder River Basin (Acre-Feet) - Wet Year Hydrologic Conditions
Reach	Reach Name	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Annual
1	Buffalo Creek	195	181	273	618	3,342	1,414	0	0	0	202	255	208	6,687
2	Middle Fork Powder River1	51	85	362	1,601	11,430	6,449	418	268	600	117	242	85	21,707
3	Middle Fork Powder River below Buffalo Creek	913	974	1,395	2,874	14,771	7,863	418	268	600	1,221	1,403	819	33,518
4	Beaver Creek	1,063	1,113	1,311	1,181	2,657	1,489	258	263	641	1,022	1,079	889	12,967
5	Beaver Creek below Blue Creek	1,063	1,187	1,355	1,181	2,657	1,489	258	263	641	1,212	1,283	889	13,479
6	Middle Fork Powder River below Beaver Creek	1,975	2,273	2,817	4,055	17,429	9,352	676	531	1,241	2,432	2,927	1,708	47,417
7	Middle Fk Powder River above Red Fk Powder	1,975	2,466	2,997	4,055	17,429	9,352	676	531	1,241	2,432	2,928	1,708	47,791
8	Red Fork Powder River	1,940	2,358	2,799	3,040	12,699	6,977	536	404	926	2,465	2,883	1,709	38,738
9	Middle Fk Powder River above N Fk Powder	3,915	4,824	5,796	7,095	30,128	16,330	1,212	935	2,167	4,898	6,001	3,418	86,718
10	North Fork Powder River	1,145	1,291	1,288	716	5,136	4,353	98	48	156	1,698	1,822	1,004	18,757
11	Powder River below N & Middle Fks Powder	5,060	6,115	7,085	7,811	35,264	20,683	1,310	983	2,323	6,596	7,823	4,422	105,474
12	Powder River above South Fork Powder	5,060	6,115	7,805	7,811	42,733	37,477	3,051	983	2,323	9,932	7,823	4,422	134,816
13	South Fork Powder River	229	1,369	8,011	6,589	17,715	5,530	1,989	2,067	15	418	370	123	44,427
14	Powder River above Salt Creek	5,290	7,484	15,096	14,400	60,729	43,564	5,694	3,051	2,642	10,350	8,193	4,544	181,036
15	Salt Creek	1,452	2,090	4,095	2,469	12,546	7,727	9,183	1,613	1,638	3,694	1,879	993	49,377
16	Powder River below Salt Creek	6,741	9,573	19,191	16,870	73,310	51,299	14,882	4,663	4,280	14,044	10,072	5,537	230,461
17	Powder River above Crazy Woman Creek	6,741	9,573	23,790	16,870	80,197	61,924	20,283	5,915	4,280	14,044	10,072	5,537	259,255
18	Crazy Woman Creek above Powder River	785	1,487	3,459	3,445	22,562	25,117	5,101	2,206	375	2,414	1,505	712	69,167
19	Powder River below Crazy Woman Creek	7,527	11,060	27,253	20,315	102,759	87,040	25,422	8,175	4,655	16,458	11,577	6,250	328,489

Note: ¹ Constrained by Instream Flow Rights of 12 cfs (July 1 - March 31) and 25 cfs (April 1 - June 30).

Table 15 Available Flow for Powder River Basin (Acre-Feet) - Normal Year Hydrologic Conditions
Reach	Reach Name	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Annual
1	Buffalo Creek	202	190	267	694	2,090	100	0	0	0	236	231	214	4,226
2	Middle Fork Powder River1	0	0	0	280	6,819	2,957	0	0	0	0	0	0	10,056
3	Middle Fork Powder River below Buffalo Creek	745	968	1,324	3,152	10,841	6,385	399	261	570	881	1,085	821	27,431
4	Beaver Creek	964	1,244	1,384	1,175	1,729	1,474	233	240	553	956	1,228	988	12,166
5	Beaver Creek below Blue Creek	964	1,290	1,402	1,175	1,729	1,566	233	240	553	956	1,228	988	12,322
6	Middle Fork Powder River below Beaver Creek	1,709	2,258	2,727	4,327	12,569	8,716	632	500	1,123	1,837	2,312	1,809	40,519
7	Middle Fk Powder River above Red Fk Powder	1,709	2,525	3,423	4,327	12,569	8,716	632	500	1,123	1,837	2,312	1,809	41,483
8	Red Fork Powder River	1,658	2,396	3,155	3,347	7,408	4,935	393	310	647	1,790	2,277	1,788	30,105
9	Middle Fk Powder River above N Fk Powder	3,367	4,922	6,579	7,674	19,977	13,651	1,025	811	1,770	3,627	4,589	3,597	71,587
10	North Fork Powder River	971	1,272	1,451	997	2,629	1,918	0	0	5	1,284	1,500	1,119	13,145
11	Powder River below N & Middle Fks Powder	4,338	6,193	8,029	8,671	22,606	16,087	1,025	811	1,775	4,911	6,089	4,716	85,251
12	Powder River above South Fork Powder	4,338	6,653	8,029	9,371	22,606	17,055	1,908	821	2,730	5,790	6,089	4,716	90,107
13	South Fork Powder River	132	1,287	7,025	5,987	6,835	2,093	1,132	1,699	17	188	213	112	26,720
14	Powder River above Salt Creek	4,470	7,940	15,054	15,358	29,441	19,403	3,580	3,010	3,353	6,189	6,302	4,828	118,929
15	Salt Creek	1,306	2,532	3,882	3,239	3,750	4,823	5,081	1,705	2,350	2,399	1,540	1,114	33,722
16	Powder River below Salt Creek	5,776	10,472	18,936	18,597	33,192	24,225	8,661	4,715	5,703	8,588	7,842	5,943	152,650
17	Powder River above Crazy Woman Creek	5,776	10,472	21,140	18,597	33,192	29,159	11,002	5,572	5,732	8,588	7,842	5,943	163,014
18	Crazy Woman Creek above Powder River	648	1,669	2,919	3,526	7,779	8,209	2,328	985	720	1,286	1,162	773	32,004
19	Powder River below Crazy Woman Creek	6,424	12,141	24,059	22,124	40,971	37,368	13,330	6,557	6,452	9,874	9,003	6,715	195,018

Note: ¹ Constrained by Instream Flow Rights of 12 cfs (July 1 - March 31) and 25 cfs (April 1 - June 30).

Table 16 Available Flow for Powder River Basin (Acre-Feet) - Dry Year Hydrologic Conditions
Reach	Reach Name	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Annual
1	Buffalo Creek	187	169	214	298	909	0	0	0	0	167	206	197	2,347
2	Middle Fork Powder River1	0	0	0	425	3,840	0	0	0	0	0	0	0	4,265
3	Middle Fork Powder River below Buffalo Creek	633	799	1,072	2,985	6,625	2,576	240	219	360	586	829	597	17,521
4	Beaver Creek	921	1,164	1,365	961	943	830	199	248	405	820	1,096	817	9,767
5	Beaver Creek below Blue Creek	921	1,164	1,399	961	943	846	199	248	405	820	1,096	817	9,817
6	Middle Fork Powder River below Beaver Creek	1,553	1,964	2,471	3,946	7,568	3,421	438	467	765	1,407	1,925	1,414	27,338
7	Middle Fk Powder River above Red Fk Powder	1,553	1,964	2,651	3,946	7,568	3,421	438	467	765	1,407	1,925	1,414	27,518
8	Red Fork Powder River	1,544	1,892	2,451	2,332	3,262	1,603	205	268	358	1,487	1,903	1,435	18,740
9	Middle Fk Powder River above N Fk Powder	3,097	3,856	5,101	6,278	10,831	5,024	643	735	1,123	2,894	3,828	2,849	46,258
10	North Fork Powder River	919	1,089	1,278	385	1,069	0	0	0	0	1,090	1,288	917	8,036
11	Powder River below N & Middle Fks Powder	4,016	4,945	6,379	6,662	11,900	5,024	643	735	1,123	3,984	5,116	3,766	54,294
12	Powder River above South Fork Powder	4,016	4,945	6,379	6,662	11,900	5,024	900	735	1,123	4,159	5,229	3,766	54,840
13	South Fork Powder River	94	1,074	3,574	2,698	3,480	564	377	864	6	90	121	84	13,026
14	Powder River above Salt Creek	4,110	6,019	9,953	9,360	15,380	5,588	1,886	1,599	1,129	4,674	5,648	3,850	69,196
15	Salt Creek	1,660	2,515	2,780	2,108	1,851	1,044	3,197	1,054	924	1,898	1,799	1,206	22,035
16	Powder River below Salt Creek	5,770	8,534	12,733	11,468	17,231	6,632	5,083	2,652	2,053	6,572	7,446	5,056	91,231
17	Powder River above Crazy Woman Creek	5,770	8,534	16,245	11,468	17,231	7,179	5,083	2,652	2,053	6,655	7,507	5,056	95,434
18	Crazy Woman Creek above Powder River	832	1,028	2,418	2,018	3,415	2,241	551	158	69	988	1,114	747	15,539
19	Powder River below Crazy Woman Creek	6,602	9,561	18,663	13,486	20,647	9,420	5,594	2,810	2,122	7,643	8,622	5,803	110,973

Note: ¹ Constrained by Instream Flow Rights of 12 cfs (July 1 - March 31) and 25 cfs (April 1 - June 30).

Table 17 Available Flow for Little Powder River Basin (Acre-Feet) - Wet Year Hydrologic Conditions
Reach	Reach Name	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Annual
1	Little Powder River above USGS gage 06324925	562	7,548	14,241	2,860	9,079	2,733	377	279	53	2,316	180	143	40,372
2	Little Powder River above USGS gage 06324970	1,195	7,548	14,241	2,860	13,237	3,354	1,044	426	226	2,722	485	375	47,714
3	Little Powder River above State Line	1,203	7,553	14,243	2,860	13,237	3,354	1,044	426	226	2,782	520	391	47,838

Table 18 Available Flow for Little Powder River Basin (Acre-Feet) - Normal Year Hydrologic Conditions
Reach	Reach Name	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Annual
1	Little Powder River above USGS gage 06324925	405	1,109	1,553	1,119	1,970	1,683	625	309	246	283	144	65	9,511
2	Little Powder River above USGS gage 06324970	548	1,493	2,209	1,396	2,190	1,894	674	337	268	450	254	142	11,853
3	Little Powder River above State Line	556	1,497	2,210	1,396	2,190	1,894	674	337	268	504	289	159	11,974

Table 19 Available Flow for Little Powder River Basin (Acre-Feet) - Dry Year Hydrologic Conditions
Reach	Reach Name	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Annual
1	Little Powder River above USGS gage 06324925	24	319	399	284	474	220	64	74	13	19	26	30	1,946
2	Little Powder River above USGS gage 06324970	60	481	630	344	560	239	105	74	17	41	54	69	2,674
3	Little Powder River above State Line	63	482	630	344	560	239	105	74	43	53	69	75	2,737

Tongue River

The allocable flows of the Tongue River drainage are to be divided between the two States in accordance with the following percentages per the Yellowstone River Compact:

Wyoming 40%
Montana 60%

This evaluation is based on the following assumptions:

• The allocation of the waters of the Tongue River is based on adjusted flow records from USGS Gage 06308500 (Tongue River at Miles City) during the study period 1970 through 1999 (Surface Water Hydrology memorandum, HKM 2002).

• Any water use under post-1950 water rights that is reflected in Gage 06308500 has occurred in both States in the same proportion as the Compact allocation (40% Wyoming / 60% Montana). These depletions are therefore not added into the flow at Miles City. The results of this evaluation therefore represent the Remaining Allocable Flow.

• The streamflow at Miles City is unaffected by storage regulation under post-1950 storage rights and adjustments are therefore not required. The enlargement to Tongue River Reservoir was completed in late 1998 and storage in the enlarged pool did not occur until June of 1999 and then only for a short time. This assumption then only results in a minor inconsistency during the 1970 through 1999 study period.

In a letter sent to the State of Montana in 1990, Wyoming has claimed a need for 18,702 acre-feet of additional water to supplement the supply of pre-1950 rights (Lowry, June 19, 1990). To fully supply these needs, additional reservoir storage with pre-1950 storage rights would likely be required.

The work sponsored by the State of Montana in 1990/1991 makes the assumption that the following four adjustments should be made to the streamflow at Miles City to account for unused pre-1950 rights or supplemental supplies to pre-1950 rights (GeoResearch Inc., July 18, 1991).

1. Depletions for Northern Cheyenne tribal water rights (31,800 acre-feet),
2. Winter bypass flow at Tongue River Dam (23,800 acre-feet),
3. Depletions for the unused 1924 priority USDA irrigation project near Miles City (1,900 acre- feet),
4. Depletions for supplemental supplies to pre-1950 rights on tributaries to the Tongue River in Montana (9,500 acre-feet).

In order to represent the wide range of possible interpretations, HKM has made two estimates of Wyoming's remaining allocation of Tongue River water per the Yellowstone River Compact (a conservative estimate and a liberal estimate) as summarized in Table 21. For the liberal estimate, the flow at Miles City is only adjusted to reflect increased depletions for supplemental supply to pre-1950 rights in Wyoming. For the conservative estimate, all of the aforementioned adjustments are included. The actual remaining allocation, to finally be determined at some undefined time in the future, will likely fall somewhere in the middle of this range of estimates.

Table 21 Wyoming's Remaining Allocation of Available Flow per Yellowstone River Compact
Hydrologic Condition	Tongue River Basin		Powder River Basin
	Conservative Estimate	Liberal Estimate
Wet Years	163,000	189,000	211,500
Normal Years	90,000	117,000	131,100
Dry Years	40,000	67,000	74,300

The derivation of these estimates is described on the worksheet provided with this memorandum. The Wyoming Water Planning Program estimated Wyoming's average annual unused and unappropriated portion of the Tongue River to be 96,400 acre-feet for the 1948 through 1968 study period (SEO, 1972).

Powder River

The allocable flows of the Powder River drainage are to be divided between the two States in accordance with the following percentages per the Yellowstone River Compact:

Wyoming 42%
Montana 58%

REFERENCES

GeoResearch Inc., July 18, 1991. Tongue River Water Allocation Model Program Documentation, for Montana Department of Natural Resources and Conservation. Helena, Montana

HKM Engineering Inc., 2002. Environmental Water Uses, Technical Memorandum, Powder/Tongue River Basin Plan. Billings, Montana

HKM Engineering Inc., 2002. Spreadsheet Model Development and Calibration, Technical Memorandum, Powder/Tongue River Basin Plan. Billings, Montana

HKM Engineering Inc., 2002. Surface Water Hydrology, Technical Memorandum, Powder/Tongue River Basin Plan. Billings, Montana

Lord Consulting, 2002, Legal and Institutional Constraints, Technical Memorandum, Powder/Tongue River Basin Plan. Laramie, Wyoming

Lowry, Sue, Wyoming Interstate Streams Engineer. June 19, 1990, Letter to Glen McDonald, Supervisor Project Rehabilitation Section, Montana Department of Natural Resources and Conservation

Tavelli, Chace, Office of the Wyoming State Engineer. October 5, 2001, Letter to Wade Irion, Project Manager, HKM Engineering regarding Compact allocations of available flow

Wyoming State Engineer's Office (SEO), April 1972, Wyoming Water Planning Program, Report 10, Water & Related Land Resources of Northeastern Wyoming, Cheyenne, Wyoming

Wyoming State Engineer's Office (SEO), 1982. Documents on the Use and Control of Wyoming's Interstate Streams - Compacts, Treaties, and Court Decrees, Cheyenne, Wyoming