The Why and How of Colorado Aug. Plan

Decrees—Maintaining Historic Return Flows

Colorado Aquifer Management Conference

American Ground Water Trust

Nov. 28-29, 2012

Jon Altenhofen, PE

South Platte Projects Manager

(Projects: ARA, PRRIP, ADI)

THE WHY and HOW:

The WHY is the GOAL of maintaining historic return flows-

Returnflows to the river (river gains from groundwater

inflows) supply downstream senior surface rights and the

junior tributary irrigation wells deplete these returnflows.

The HOW is a Colorado Water Court approved

Augmentation Plan. Numerous Terms and Conditions

with much emphasis on:

(a) Tributary Aquifer Response Functions for lagging

activities at wells/recharge ponds to future

depletions/accretions at the river in terms of amount,

timing and location.

(b) Water Balance Accounting (for actual and projections) at

the river listing ALL depletions versus replacement

supplies so negative effects are fully augmented/replaced

so no shortages to demands of senior downstream rights.

Historical South Platte River Flows—

Pre-Irrigation John Charles Fremont, Explorer, July 1842

”six miles from our resting place near Julesburg we crossed the bed of a considerable stream, now entirely dry ---a bed of sand.”

Post-Irrigation Ralph Parshall, Colorado A&M College Report, 1922

“The practice of irrigating … maintains a constant return flow … beyond all expectations … Perhaps no other Colorado stream has such an abundant return flow as the South Platte River.”

Post- Well Irrigation Ralph Parshall, Talk to Ft. Collins Rotary Club, Aug. 29, 1956 titled “The

Water Problem”

“…the area north and south of the river between Kersey and Julesburg, more than 4000 irrigation wells are being pumped…we cannot continue this practice of depleting the underground reservoir at the present rate….The depletion of the return flow to the river is going to have a marked effect upon … senior rights along the South Platte.”

South Platte Basin

Point Flow analysis for Monday Nov 26, 2012 at 1500 hrs

http://www.lspwcd.org/index_files/POINTFLOW2.htm

A point flow analysis shows the important fact of SP hydrology-it’s a return

flow hydrology and administration/aug. plan decrees protect that fact.

South Platte Tributary Alluvial

gains/returnflows to the lower river of about

2 cfs/mile on June 15, 1994

S. Platte at Tamarack

from Red Lion Bridge

June 15, 1994; 25 cfs

I&PV

60 cfs

& call

Hmy1

34 cfs

Peter

41 cfs

Divs. drying

the river

25 cfs at StLi

Compact Call

Pic

Looking west

upstream

--The South Platte tributary aquifer is an

“unconfined Valley Fill surficial aquifer”; an

alluvial aquifer made up of sands and gravels.

USGS estimated volume of groundwater storage at

about 8 MAF.

--USGS estimated 1 MAF annually of recharge to

the aquifer from canal/reservoir seepage and on-

farm deep percolation.

--The South Platte River forms a natural drain for

the alluvial aquifer. Groundwater seepage to S.

Platte River averages about 515,000 af/yr (USGS).

Some Groundwater Numbers for the

South Platte in Colorado

Alluvial Wells

Effects of an Alluvial Well Alluvial Irrigation Well Cons. mass/energy

Decreed Augmentation Plans

USGS in cooperation with

the Colorado Water

Conservation Board

(CWCB)

Six S. Platte Reaches

(Brighton, Greeley,

Weldona, Brush, Sterling,

Julesburg)

Six Maps each Reach

(well locations, bedrock and

water table contours,

saturated thickness,

transmissivity, and Stream

Depletion Factor; SDF in

days)

Timing of Lagged Groundwater Response at River

AWAS Computation Options (Alluvial Water Accounting System)

--- SDF (Effective Stream Depletion Factors via Jenkins)

– Glover Methods (i.e., alluvial aquifer-no flow boundary

condition)

– URFs via Numerical Groundwater Model (ie; MODFLOW)

http://www.ids.colostate.edu/projects.php and go to ‘IDS AWAS’

Timing

example

using

SDF

Method

(Days)

USGS SDF contour lines

(one-pt calibration at

28% effect)

Alluvial Aquifer Grid for T, X, W

• Appendix C

• Tamarack Ranch State Wildlife Area Recharge Project

• Unit Replacement Factors for All Recharge Ponds

• Month Pond 1 Pond 2 Pond 3 Pond 4

•

• 1 0.1012 0.2477 0.1005 0.0264

• 2 0.2213 0.2815 0.2217 0.1281

• 3 0.1459 0.1250 0.1542 0.1509

• 4 0.1000 0.0744 0.1062 0.1289

• 5 0.0748 0.0521 0.0783 0.1035

• 6 0.0589 0.0397 0.0608 0.0831

• 7 0.0465 0.0306 0.0472 0.0653

• 8 0.0383 0.0247 0.0383 0.0531

• 9 0.0314 0.0200 0.0309 0.0428

• 10 0.0260 0.0163 0.0252 0.0348

• 11 0.0238 0.0155 0.0227 0.0284

• 12 0.0201 0.0131 0.0189 0.0231

• 13 0.0172 0.0113 0.0160 0.0191

• 14 0.0149 0.0098 0.0136 0.0158

• 15 0.0129 0.0085 0.0116 0.0131

• 16 0.0112 0.0075 0.0100 0.0128

• 17 0.0098 0.0065 0.0087 0.0109

• 18 0.0087 0.0058 0.0077 0.0095

• 19 0.0078 0.0052 0.0068 0.0084

• 20 0.0070 0.0048 0.0059 0.0073

• 21 0.0063 0.0054 0.0065

• 22 0.0057 0.0049 0.0058

• 23 0.0054 0.0045 0.0053

• 24 0.0049 0.0048

• 25 0.0044

• 26 0.0040

• 27 0.0039

• 28

• 29

• 30

• 31

•

• Total 1.0000 1.0000 1.0000 1.0000

URFs (Unit Response

Functions) developed

for Tamarack from

MODFLOW numerical

model

http://dwrweblink.state.co.us/dwr

weblink/search.aspx

Table 1-1

Lower Logan Well Users (LLWU) Inc.03CW208 UPDATED ACCOUNTING THROUGH AUGUST 2012

MONTHLY ACCOUNTING FORM / TABLE

Depletions and Augmentation Supplies

Water Year: 2012

Nov11 Dec Jan12 Feb Mar April May June July Aug Sept Oct Totals

Days in month 30 31 31 28 31 30 31 30 31 31 30 31 for Wtr Yr

DEPLETIONS(a) Irrigation Well Depletions for senior wells (senior to 2-28-1972, #44618); 1974-Current Pumping -987 -868 -785 -721 -667 -640 -868 -1483 -1657 -1888 -2049 -1495 -14108

(b) Irrigation Well Depletions for 2 most junior wells with No Court Decree; 1974-Current Pumping -45 -53 -59 -63 -68 -56 -35 -27 -36 -38 -31 -39 -550

(c) Augmentation Well Depletions above the Harmony #1 -- Due to Aug Well use thru Previous WY (App Date 6-15-2004, #56414) -5 -5 -5 -4 -4 -4 -4 -4 -3 -3 -3 -3 -47

(d) Historic Return Flows -- Due to Prewitt Res. releases thru Previous WY (App Date 4-30-2003, #56002) -9 -8 -8 -8 -8 -7 -7 -7 -7 -6 -6 -6 -87

(e) Recharge Well Depletions -- Total through current pumping (App Date 4-30-2003, #56002) -38 -1487 -2777 -2945 -2657 -1308 -165 -74 -56 -47 -40 -35 -11629

The net effect below Harmony #1 is added in below

W = Total Depletions Above Harmony #1 -1084 -2421 -3634 -3741 -3404 -2015 -1079 -1595 -1759 -1982.2 -2128.8 -1578 -26421

AUGMENTATION REPLACEMENT SUPPLIESRecharge Accretions Occurring above the Harmony #1

Bravo Ditch areas and Bravo recharge sites 384 451 562 673 818 806 756 578 561 474 414 392 6869

Iliff & Platte Valley Ditch areas and IPV recharge sites 76 77 75 69 73 70 72 70 72 72 69 71 866

Harmony #2 Ditch areas and UHD recharge sites 4 5 5 5 6 6 6 6 6 7 6 7 69

Powell Ditch areas and PWC recharge sites 0 0 0 0 0 0 0 0 0 0 0 0 0

SLC recharge sites 540 533 510 467 507 514 559 560 583 574 540 536 6423

SSLC recharge sites 96 88 102 180 301 299 248 189 164 138 113 98 2016

StLC recharge sites 164 160 170 184 226 238 244 217 202 183 163 157 2308

LC recharge sites 107 105 101 95 107 111 121 119 121 116 108 106 1317

KF recharge sites 0 0 0 0 0 0 0 0 0 0 0 0 0

Ramsey recharge sites 39 40 16 9 8 35 37 15 10 8 7 6 230

Golden Eagle's use of Rech Acc -6.19 -4.80 -1.36 -0.57 -0.46 -0.36 -9.55 -2.37 -0.68 -0.46 -0.34 -7.76 -34.9

The net effect below Harmony #1 is added in below

Total Accretions Above Harmony #1 (A) 1403.81 1454.2 1539.64 1681.43 2045.54 2078.64 2033.45 1751.63 1718.32 1571.54 1419.7 1365.24 20063

Other Aug Credits

Harris 00CW181 Decree Computations -24.7 -16.5 -10.5 -5.9 -10.8 6.2 -4.1 -25.1 -0.2 -25.6 -41.7 -41.6 -200

Net Credit from Other Sources Above Harmony #1 (B) -25 -17 -11 -6 -11 6 -4 -25 0 -26 -42 -42 -200

Prewitt Reservoir releases and augmentation well pumping done on days of river call.

Call Analysis and resulting Net Shortage/Excess on Call days Monthly Call Records: NO CALLS in Nov-Dec 2011 & Jan-Feb 2012Senior call; 25.33 days May, 30 days June, 31 days July, 31 days Aug

6 days of senior and 4 days of junior calls in April 2012

Days of Senior River Call above the Harmony #1 0 0 0 0 0 6 25.33 30 31 31 30 31 184

W1 = Net Shortage/Excess on Senior call days above Harmony #1 (W+A+B)*%call days 0 0 0 0 0 14 777 132 -41 -436 -751 -254 -560

Days of Junior Call above the Harmony #1 0 0 0 0 0 4 0 0 0 0 0 0 4

W1 = Net Shortage/Excess on Junior call days [(Sum rows b thru e above)+A+B]*%call days 0 0 0 0 0 95 0 0 0 0 0 0 95

Which of rows b thru e above are summed depends upon which junior call Projections in Red Julesburg Res Junior Call Mar 27-31, 2012 and Res full Mar 31

Prewitt Reservoir Releases in WY2012

Gross Credit=Release minus river shrink 0 0 0 0 0 0 0 0 89 650 413 0 1152

Depletions from Release (Replace Historic Returns) on days of call (App Date 4-30-2003, #56002) 0 0 0 0 0 0 0 0 -10 -73 -72 -33 -188

Net Credit from Release (C) 0 0 0 0 0 0 0 0 79 577 341 -33 964

Projections in Red

Augmentation Well Pumping in WY2012

Total Pumping for credit (at average aug well and 95% conveyance to river for projection) 620 470 1090

Depletions from this Pumping on days of call (App Date 6-15-2004, #56414) 0 0 0 0 0 0 0 0 0 0 -21 -92 -113

Net Credit Aug Wells (D) 0 0 0 0 0 0 0 0 0 0 599 378 977

Exchange Operations Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct

Y = Total Diversions (See Table 1-2C) 0 0 0 0 0 0 0 0 0 0 0 0 0

NET EFFECT ABOVE HARMONY #1 (X = W1+C+D-Y) ON CALL DAYS (Senior and Junior) 0 0 0 0 0 109 777 132 38 141 189 91 1475

Senior call; 17.16 days May, 30 days June, 31 days July, 31 days Aug

Affects Occurring Below the Harmony No. 1 Headgate Senior Call Admin #= No Senior Calls Nov11-Apr. 2012

Days of Senior River Call below the Harmony #1 0 0 0 0 0 0 17.16 30 31 31 30 15 154

Irrigation Well Depletions for senior wells Occurring below the Harmony #1 (senior to 2-28-1972, #44618); 1974-Current Pumping -206 -176 -156 -140 -128 -120 -127 -167 -230 -286 -316 -289 -2341

Augmentation Well Depletions below the Harmony #1 -- Due to Aug Well use thru Previous WY (App Date 6-15-2004, #56414) -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -12

Augmentation Well Depletions below the Harmony #1 -- Due to Aug Well use in Current WY (App Date 6-15-2004, #56414) 0 0 0 0 0 0 0 0 0 0 0 0 0

UHD and Svoboda Recharge Site 128 117 133 208 291 317 315 247 197 159 131 118 2361

Z = Net Effect Below Harmony No. 1 on call days 0 0 0 0 0 0 104 79 -34 -128 -186 -83 -249

cfs for Augmentation below Hmy #1= 0.6 2.1 3.1 2.8

NET EFFECT (X+Z) ON CALL DAYS (Senior and Junior) 0 0 0 0 0 109 880 211 4 13 3 7 1227

Row AA; Net Effect for Entire Month if Positive 266 1137 211 1614

If there is no call or compact condition below the Harmony #1 then amount Z does not have to be replaced and is not included in this Final NET EFFECT Row.

Recharge well depletions in a month when recharge wells are pumped in-priority after call comes off based on recharge well pumping thru prior month.

Accounting Forms prepared by Jon Altenhofen, NCWCD; Joe Frank, LSPWCD; and TZA Water Engineers, Inc.

Augmentation Challenge—

Replacement of ALL “out of priority” junior well depletions to a downstream senior (calling) right in time, location, and amount

Passive Augmentation Supply – Less Control on augmentation credit at the river

• Managed Groundwater Recharge

Active Augmentation Supply – More Control over augmentation credit at the river – BUT cause an additional depletion / return flow replacement

• Augmentation Wells

• Reservoir Release to River

• Ditch Bypass at River Headgate

Managed Groundwater Recharge

Effects of Groundwater Recharge (both managed and unmanaged)

Managed Groundwater Recharge Site

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South Platte Recharge

Total District 1, 2, & 64 Recharge

District 1 Recharge

District 64 Recharge

District 2 Recharge

http://www.ids.colostate.edu/projects/awas/files/Recharge_as_Augmentation_in_SP.pdf

This TR-21 is 2nd

Edition from 1994;

1st Edition was TR-13

from 1986

Recharge and Augmentation Well System near

Sedgwick, CO

SUMMARY: A sustainable S. Platte alluvial aquifer has developed

through irrigation and this aquifer has enhanced Colorado

irrigation and water use through return flows and

groundwater pumping.

The challenge is to continue to utilize the aquifer through

droughts, growing demands, and increased legal

augmentation requirements while maintaining historic

return flows.

Maximizing the aquifer storage potential through such

activities as managed groundwater recharge and

augmentation wells (i.e., with proper analysis/accounting for

net river effects) can meet current and future challenges

to maintain/maximize beneficial use without injury.

Recharge at Sunset

on the Overland

Trail Ranch

Recharge pond with

snow geese at

Condon Ranch

The End

Questions/Comments

Prepare for drought continuing

in 2013—

Wells will be essential but their

effects on river returnflows

must be augmented else

downstream seniors see a

compounded drought effect