Attachment 2

Analysis of Measures that would have been Required for Nebraska to Achieve Water-

Short Year Compliance with Republican River Compact in 2006

Report

to

David Barfield, P.E.

Chief Engineer

Kansas Department of Agriculture, Division of Water Resources

from

Dale E. Book, P.E.

Spronk Water Engineers, Inc.

April 21, 2008

Page -1-

Spronk Water Engineers was requested to develop an estimate of the combination of

reduction in surface water use and groundwater pumping that would have been necessary

for Nebraska to achieve compliance with the Water-Short Year test for 2006 as required by

the Final Settlement Stipulation (FSS) approved in Kansas v. Nebraska & Colorado. The

purpose of this analysis was therefore to determine the extent to which surface water was

available to reduce Nebraska’s overuse in 2005 and 2006 and the remaining reduction in

pumping that would have been necessary to completely eliminate Nebraska’s overuse. The

effect of pumping reduction on streamflow was determined by the Groundwater Model

adopted in the FSS, as amended by the Republican River Compact Administration (RRCA).

The analysis incorporates the FSS accounting procedures to determine the effects of the

pumping reduction on allocations and Computed Beneficial Consumptive Use (CBCU).

Based upon the amount of surface water available, the pumping reduction necessary for

compliance was determined with the Groundwater Model. The effects were then included

in the accounting to determine the amount of surface water that would have been required.

The following is a description of the FSS accounting spreadsheet analysis, which takes into

account the interaction of surface and groundwater effects. The electronic versions of the

spreadsheets are provided herewith.

Pumping was removed on 140,858 acres in 2005 and 121,332 acres in 2006, corresponding

to an area approximately equivalent to a one-mile wide area along the streams in Nebraska.

This was accomplished by removing pumping from the model stream cells, as described in

Attachment 3. The RRCA GW Model was used to compute the effects of this reduced

pumping for the years 2005 and 2006. Impacts of this change compared to the historical

condition were 14,900 af in 2005 and 26,300 af in 2006, expressed as reductions in GW

(CBCU). Table 1 shows the changes in GW CBCU determined by the model.

The changes to streamflow were evaluated with the RRCA accounting spreadsheets to

estimate the benefit to compact compliance for the two years. The analysis required

assumptions about the changes in diversions, storage and reservoir evaporation that would

have resulted. The changes in GW CBCU were made by tributary and reach. It was assumed

that none of the additional flow would have been stored or evaporated, but would have been

added to the streamflow or diverted by canals. This assumption is somewhat idealized, since

some reregulation of gains to match the diversion season would occur in the system.

It was assumed that the shortfall remaining after accounting for the effects of the pumping

reduction could have been offset with additional purchase of surface water. The surface

Page -2-

water supply was estimated from the diversions reported in the compact accounting sheets

for the two years.

The availability of reservoir storage was also considered for the purpose of offsetting the

two-year shortfall. Based on reservoir storage contents at the end of 2006, the estimated

available storage was approximately 28,000 acre-feet, located primarily in Swanson and

Strunk Reservoirs. Table 2 shows the reservoir storage status at the end of 2006. It should

be noted that when storage is released, it has the effect of changing the water supply and

allocations. Release of stored water would be about 50 % effective for reducing the amount

of Nebraska overuse. This assumes that the water would have been released and delivered

to Kansas.

The RRCA compact accounting sheets for the two years were adjusted to reduce the GW

CBCU and incorporate the release of 28,000 af of storage in 2006. The results for compact

accounting for the Water-Short Year test for 2006 are provided in Table 3. The effects, as

measured at Guide Rock, are summarized as follows:

1. Overuse of Compact Allocation in 2005 - 2006 79,100 af.

2. Amount of reduced GW CBCU

(Deduction from overuse) 39,100 af

3. Amount of increased SW CBCU

(Addition to overuse) 7,300 af

4. Increase in Nebraska Allocation 15,000 af

5. Remaining Overuse of allocation after applying

Available surface water supply is summarized in Table 4. The projected surface water

diversions total 95,900 af for the two years, with associated CBCU of 44,600 af. It is

assumed for purposes of this analysis that most of these surface water supplies could have

been acquired for compact compliance and not used for irrigation. It should be noted that

approximately 15% of the CBCU was associated with the small pumps and non-federal

ditches and the ability to obtain these small supplies is questionable.

The amount of diversion corresponding to 32,300 af of CBCU would have been

compact compliance and the application of the available surface water supply to offset the

shortfall. Because the compliance is assessed on a two-year basis, the application of surface

Page -3-

water to the shortfall could have varied from the values computed for each year.

The total available surface water, including storage at the end of 2006 and diversions, was

estimated to be 124,000 af. Approximately 81% was calculated to be necessary to offset the

overuse, after considering the pumping reduction.

The delivery of surface water downstream to offset overuse would result in some transit loss

between the upstream locations of use and the Stateline. Therefore, there would not be a

one-to-one correspondence between reduction of SW CBCU in Nebraska or reservoir

releases and streamflow at the Stateline. However, for purposes of estimating the amount

of surface water necessary to be retired, transit losses were not estimated. It is expected that

the actual amount of surface water needed would have exceeded the amount obtained from

these calculations, due to occurrence of some transit loss.

There are several key assumptions in this analysis:

• It has been assumed that the surface water could have been acquired and delivered

downstream, without incurring significant evaporation, for same year deliveries to

KBID.

• It has been assumed that the storage available in the project reservoirs is the amount

in excess of the contracted water levels, without additional constraints.

• Transit losses to deliver surface water to Kansas have not been added to the amounts

needed to be provided.

The reduction in acreage irrigated by groundwater pumping was 140,858 acres in 2005 and

121,332 acres in 2006. The total surface water needed would have been 100,800 af at the

river or reservoir This would equate to farm deliveries of 47,000 af. Because the use of

surface water CBCU for this analysis was considered fully effective to offset Nebraska’s

overuse, without any transit loss added, the amount of surface water actually necessary to

achieve compliance would have been higher.

Table 1 Summary of Reduced Ground Water Computed Beneficial Use

(GW CBCU)

Table 2 Storage Available for Release in 2006

Table 3 Estimated Effect on Compliance from Reduction in Nebraska's

Pumping and Reservoir Releases: 2005-2006 (water-short)

Table 4-A Nebraska's Surface Water Use Summary: 2005

Table 4-B Nebraska's Surface Water Use Summary: 2006

Table 5 Summary of Analysis of Nebraska Compliance

4/21/2008

Summary of Reduced Ground Water Computed Beneficial Consumptive Use (GW CBCU)

2005 -2006

acre-ft

Subbasin 2005 2006

Arikaree 73 73

Beaver 0 0

Buffalo 74 173

Driftwood 99 234

Frenchman 5,686 5,674

North Fork 131 44

Above Swanson 2,533 3,088

Swanson - Harlan -3,771 7,819

Harlan - Guide Rock 6,845 5,445

Guide Rock - Hardy 1,045 995

Medicine 1,597 2,012

Prairie Dog 0 0

Red Willow 41 103

Rock 1 6

Sappa 0 0

South Fork 108 371

Hugh Butler 82 3

Bonny 0 0

Keith Sebelius 0 0

Enders 101 82

Harlan 96 52

Harry Strunk 27 11

Swanson 109 99

Change in Net Nebraska

Impacts

4/21/2008

Table 2

Storage Available for Release in 2006

1000 acre-ft

Reservoir

EOM

Storage

Available for

Release in 2006

Enders 10.7 8.9 1.8

Harlan Co 116.1 118 0.0

Harry Strunk 17.7 8.9 8.8

Hugh Butler 12.1 11.2 0.9

Swanson 37.3 20.9 16.4

Total 27.9

(1) Source: ResStorChange06.xls

(2) Minimum Storage is minimum contracted water level

4/21/2008

Year

State-Wide

Allocation

Allocation

Below Guide

Rock

Allocation

Above Guide

Rock

State-Wide

CBCU

CBCU Below

Guide Rock

CBCU Above

Guide Rock

Year

State-Wide

Allocation

Allocation

Below Guide

Rock

Allocation

Above Guide

Rock

State-Wide

CBCU

CBCU Below

Guide Rock

CBCU Above

Guide Rock

Source: RRCA Accounting Spreadsheets with adjustments made to Nebraska's GW CBCU

Note: Adjusted values assume no change in reservoir storage and evaporation while evacuating reservoirs in 2006 to their operational minimum.

Adjusted

Allocation Computed Beneficial Consumptive Use Imported Water

Supply Credit

above Guide

Rock

Allocation -

(CBCU - IWS

above Guide

Rock)

Allocation Imported Water

Supply Credit

above Guide

Rock

Allocation -

(CBCU - IWS

above Guide

Rock)

Computed Beneficial Consumptive Use

Actual

4/21/2008

Table 4-A

Nebraska's Surface Water Use Summary

2005 RRCA Accounting

acre-ft

Canal Surface Water Canal Surface Water

Sub Basin Canal Diversions Pumping CU Factor CU Diversions Pumping CU Factor CU

North Fork Haigler 4 ,745 60% 2,847 4 ,745 60% 2,847

Arikaree Non-Federal - - - -

Small Pumps - - - -

Buffalo Non-Federal 171 60% 103 171 60% 103

Small Pumps 34 75% 26 34 75% 26

Rock Non-Federal - - - -

Small Pumps - - - -

South Fork Hale - - - -

Non-Federal - - - -

Small Pumps - - - -

Frenchman Champion - - - -

Riverside 2 ,096 60% 1,258 2 ,096 60% 1,258

Culbertson 6 ,562 22% 1,438 9 ,506 22% 2,083

Culbertson Canal Extension - - - -

Non-Federal - - - -

Small Pumps 1 75% 0.8 1 75% 0.8

Driftwood Meeker-Driftwood - - - -

Non-Federal - - - -

Small Pumps - - - -

Red Willow Red Willow - - - -

Non-Federal - - - -

Small Pumps 123 75% 92 123 75% 92

Medicine Creek Non-Federal - - - -

Small Pumps 259 75% 194 259 75% 194

Non-Federal - Below Gage - - - -

Small Pumps - Below Gage 78 75% 59 78 75% 59

Beaver Non-Federal - - - -

Small Pumps - - - -

Non-Federal - Below Gage - - - -

Small Pumps - Below Gage - - - -

Sappa Non-Federal - - - -

Small Pumps 54 75% 41 54 75% 41

Non-Federal - Below Gage - - - -

Small Pumps - Below Gage - - - -

Prairie Dog Almena - - - -

Non-Federal - Below Gage - - - -

Small Pumps - Below Gage 21 75% 16 21 75% 16

Mainstem Bartley - - - -

Cambridge 1 9,732 46% 9,153 2 4,508 46% 11,368

Naponee - - - -

Franklin - - - -

Franklin Pump - - - -

Superior 4 ,712 36% 1,687 6 ,081 36% 2,177

Courtland - - - -

Non-Federal 1,661 60% 997 1,661 60% 997

Small Pumps 1,918 75% 1,439 1,918 75% 1,439

Non-Federal - Below Guide Rock - - - -

Small Pumps - Below Guide Rock 1,278 75% 959 1,278 75% 959

3 7,847 5,598 20,306 4 6,936 5,598 23,657

Source: RRCA Accounting Spreadsheets with adjustments made to Nebraska's GW CBCU.

Note: Adjusted diversions using assumption of no change in reservoir storage and evaporation.

Total

Historical Adjusted

4/21/2008

Table 4-B

Nebraska's Surface Water Use Summary

2006 RRCA Accounting

acre-ft

Canal Surface Water Canal Surface Water

Sub Basin Canal Diversions Pumping CU Factor CU Diversions Pumping CU Factor CU

North Fork Haigler 4 ,418 60% 2 ,651 4 ,418 60% 2,651

Arikaree Non-Federal - - - -

Small Pumps - - - -

Buffalo Non-Federal 170 60% 1 02 170 60% 102

Small Pumps - - - -

Rock Non-Federal - - - -

Small Pumps - - - -

South Fork Hale - - - -

Non-Federal - - - -

Small Pumps - - - -

Frenchman Champion - - - -

Riverside - - - -

Culbertson - - 2 ,919 44% 1,284

Culbertson Canal Extension - - - -

Non-Federal - - - -

Small Pumps - - - -

Driftwood Meeker-Driftwood - - - -

Non-Federal - - - -

Small Pumps - - - -

Red Willow Red Willow - - - -

Non-Federal - - - -

Small Pumps 121 75% 9 1 121 75% 91

Medicine Creek Non-Federal - - - -

Small Pumps 305 75% 2 29 305 75% 229

Non-Federal - Below Gage - - - -

Small Pumps - Below Gage 94 75% 7 1 94 75% 71

Beaver Non-Federal - - - -

Small Pumps - - - -

Non-Federal - Below Gage - - - -

Small Pumps - Below Gage - - - -

Sappa Non-Federal - - - -

Small Pumps 22 75% 1 7 22 75% 17

Non-Federal - Below Gage - - - -

Small Pumps - Below Gage - - - -

Prairie Dog Almena - - - -

Non-Federal - Below Gage - - - -

Small Pumps - Below Gage 21 75% 1 6 21 75% 16

Mainstem Bartley 5 ,830 44% 2 ,553 5 ,830 44% 2,553

Cambridge 1 9,692 45% 8 ,813 2 5,675 45% 11,490

Naponee - - - -

Franklin - - - -

Franklin Pump - - - -

Superior - - - -

Courtland - - - -

Non-Federal 2,460 60% 1 ,476 2,460 60% 1,476

Small Pumps 590 75% 4 43 590 75% 443

Non-Federal - Below Guide Rock - - - -

Small Pumps - Below Guide Rock 697 75% 5 23 697 75% 523

2 9,940 4,480 1 6,982 3 8,842 4,480 20,944

Source: RRCA Accounting Spreadsheets with adjustments made to Nebraska's GW CBCU.

Note: Adjusted diversions using assumption of no change in reservoir storage and evaporation.

Historical Adjusted

Total

4/21/2008

Summary of Analysis of Nebraska Compliance

2005 2006 Total

(2) Reduced GW CBCU 13.8 25.3 39.1

(4) Change in Allocation 0.4 14.6 15.0

(6) Surface Water Diversions 34.1 38.8 72.9

(7) SW Delivered to Farm 14.3 19.0 33.3

(8) CBCU 14.4 17.9 32.3

(9) Reservoir Storage 0.0 27.9 27.9

Notes:

Totals are above Guide Rock

canal loss 58% 51%

field efficiency 70% 70%

(1) Actual results from Table 3

(2) Reduced GW CBCU from Table 1

(3) Increased SW CBCU from Adjusted CU in Table 4-A and 4-B

(4) Difference between adjusted and actual allocation above Guide Rock on Table 3

(5) Intermediate Compliance = (1) + (2) + (3) + (4)

(6) Required at river diversions

(7) SW Delivered to Farm = (6) * (1 - Canal Loss)

(8) CBCU = (7) * field efficency + consumption of return flows

(9) Storage water available for release from Table 2

(10) Total Required @ River or Reservoir = (6) + (9)

(11) Total Required @ Field = (7) +((8) * (1 - Canal Loss))

Table 5

2005 - 2006

(1000 Acre-feet/year)

4/21/2008