hdrinc.com

4401 West Gate Blvd., Suite 400, Austin, TX 78745-1469

(512) 912-5100

July 13, 2017

Mr. Jeff Walker

Executive Administrator

Texas Water Development Board

P.O. Box 13231

1700 North Congress Avenue

Austin, TX 78711-3231

Dear Mr. Walker,

The Brazos G Regional Water Planning Group (Brazos G Group) requests that the Texas Water Development

Board consider a proposed amendment to the 2016 Brazos G Regional Water Plan (2016 Plan) related to the

City of Waco’s intent to provide treated water to ten utilities in McLennan County in order to mitigate

arsenic contamination issues in those utilities’ existing supplies. The Brazos G Group met in a regularly-

posted public meeting on April 5, 2017, and directed HDR to provide information regarding the proposed

amendment to the TWDB for concurrence that this amendment can be considered “minor.”

The Brazos G Group and the applicant, the City of Waco, believe this proposed amendment qualifies as a

“minor” amendment to the 2016 Plan based on the criteria set-forth in 31 TAC §357.51 (c):

• It does not result in over allocation of an existing or planned source of water.

• It does not relate to a new reservoir.

• It does not have a significant impact on instream flows, environmental flows, or freshwater flows to

bays and estuaries.

• It does not have a significant impact on water planning or previously adopted management strategies.

• It does not delete or change any legal requirements of the plan.

A description of the proposed amendment is enclosed for your review.

The Brazos G Group plans to formally consider this amendment at its next meeting, scheduled for August 16,

2017. Please notify us of your decision prior to this date so that the Brazos G Group can act on the matter

accordingly.

Should you have any questions regarding this proposed amendment, please contact me at (512) 912-5136

or via email at david.dunn@hdrinc.com. On behalf of the Brazos G Regional Water Planning Group, we

appreciate your consideration of this request.

Sincerely,

HDR Engineering, Inc.

David D. Dunn, PE

Vice President

CC: Brazos G Regional Water Planning Group

Stephen Hamlin, BRA

Thomas Barnett, TWDB

Lisa Tyer, City of Waco

hdrinc.com 4401 West Gate Blvd., Suite 400, Austin, TX 78745-1469 (512) 912-5100

1

Memo Date: Thursday, July 13, 2017

Project: Brazos G Regional Water Plan

To: Brazos G Regional Water Planning Group

From: David D. Dunn, PE

Subject: Proposed City of Waco amendment to the 2016 Brazos G Regional Water Plan – McLennan County Supply

At its April 5, 2017 meeting, the Brazos G Regional Water Planning Group (Brazos G) directed

HDR and the Brazos River Authority (BRA) to coordinate with the City of Waco and facilitate

development of the materials necessary to amend the 2016 Brazos G Regional Water Plan

(2016 Plan) as requested by the City. This memorandum describes the proposed amendment.

Information presented in this memorandum is taken from a draft LAN document provided by the

City of Waco1.

The City of Waco intends to supply treated water to ten utilities in McLennan County. For nine

of the utilities, the water is to be used to blend with existing groundwater supplies that exceed

the U.S. EPA’s Maximum Contaminant Level (MCL) for arsenic in drinking water of 0.01 mg/L2.

The intent is to blend treated water provided by the City of Waco with groundwater produced by

each utility such that the resulting target blended arsenic concentration in water delivered to

each utility’s customers is 15% below the MCL, or 0.0085 mg/L. The following table is copied

from the draft report to illustrate the approach.

1 Lockwood, Andrews & Newman, Inc., DRAFT McLennan County Water Supply Plan: Arsenic Mitigation

Breakout Plan, prepared for the McLennan County Water Resources Group, January 20, 2017. 2 A tenth utility, H & H WSC, is not violating the arsenic MCL, but desires to purchase 0.45 MGD supply

from Waco.

hdrinc.com 4401 West Gate Blvd., Suite 400, Austin, TX 78745-1469 (512) 912-5100

2

The locations of the nine arsenic-impacted utility systems are shown in the following figure,

copied from the draft LAN report. Nine of the ten utilities are included in the McLennan County-

Other Water User Group (WUG); only the City of Riesel is a specific Municipal WUG in the 2016

Plan.

The amounts to be supplied by Waco in 2070 are presented in the table above as “Peak Day”

demands (million gallons per day, MGD). Annual demands in 2070 were calculated by HDR by

applying a Peak-Day to Average-Day peaking factor of 2.0, which is the standard peaking factor

utilized to estimate water supplies in the 2016 Plan, and converting units to acre-feet per year

(acft/yr). Demands for other decades were determined from Appendix B in the draft report, in

which Maximum Day Demands are presented for years 2020 – 2070, and the ratio of Waco

supply to total supply from the table above. The resulting water to be supplies by Waco is

shown in the following table. For the City of Riesel, the ratio of Waco supply to total supply was

applied to the annual demands from the 2016 Plan. For H & H WSC, the desired Peak-Day

purchase from Waco was used directly, adjusted to an annual supply using the 2.0 peaking

factor.

hdrinc.com 4401 West Gate Blvd., Suite 400, Austin, TX 78745-1469 (512) 912-5100

3

Annual Supply from Waco (acft/yr)

Utility 2020 2030 2040 2050 2060 2070

Axtell WSC 135.4 145.5 155.9 167.7 180.1 193.5

Birome WSC - Plant 5 Only 13.9 15.0 15.8 16.8 17.6 18.7

Elk Oak Lake WSC 162.6 177.8 194.2 212.1 231.5 252.9

H & H WSC 252.0 252.0 252.0 252.0 252.0 252.0

Leroy-Tours-Gerald WSC 79.2 86.4 94.1 102.4 111.2 121.1

Moore Water System 40.1 40.1 40.5 41.0 41.4 41.8

Meier Settlement WSC 15.5 15.5 15.7 15.9 16.2 16.4

Prairie Hill WSC 189.1 198.7 209.2 220.1 231.9 244.2

Riesel-Meier Settlement WSC 84.0 98.1 114.9 134.7 157.6 184.5

City of Riesel 77.5 77.5 77.5 78.1 79.8 82.1

Total from City of Waco 1,049.4 1,106.7 1,169.9 1,240.9 1,319. 1,407.1

The following is a summary of the supply/demand balance for the City of Waco from the 2016

Plan. As shown, the City of Waco supplies will not be over allocated with these additional

demands.

2020 2030 2040 2050 2060 2070

Waco Demands1

37,481 37,706 37,475 37,386 38,148 40,576

Waco Supply2

50,400 50,400 50,400 50,400 50,400 50,400

Balance 12,919 12,694 12,925 13,014 12,252 9,824

1. Demands include all freshwater demands for the City of Waco as a Wholesale Water Provider,

including recommended water management strategies.

2. Waco’s total freshwater supply of 85,477 acft/yr is constrained by existing treatment capacity.

Note: All demands shown in acft/yr.

The systems were combined into the following three groups for purposes of determining the

required infrastructure costs to deliver the water from the Waco system to the individual utilities.

Utilities within each group would share that group’s respective infrastructure costs.

Group 1: Axtell, Elk Oak Lake, Moore, Prairie Hill, Birome

Group 2: Meier Settlement, Reisel-Meier Settlement, City of Riesel, H & H

Group 3: Leroy-Tours-Gerald

The various projects for each group are shown in the attached maps, copied from the draft LAN

report. The costs for these projects will be determined using the TWDB Unified Costing Model,

so to be consistent with the costs of other strategies in the 2016 Plan.

This proposed amendment would utilize existing supply from Lake Waco to provide up to 1,400

acft/yr of supply in 2070 for McLennan County-Other users and the City of Riesel.

Implementation of this supply strategy will not over allocate supplies from Lake Waco and

should be considered a “minor” amendment to the 2016 Brazos G Plan.

!

!!

!

!

!!!

DBirome Plant 5

20

12

16

1012

12

16

10

16

12

1216

12

16

16

1616

16

16

EOL WSC EOL WSCEOL WSC

AXTELL WSC

AXTELL WSC

PRAIRIE HILL WSC

PRAIRIE HILL WSC

MOORES WATER SYSTEM

Proposed 6" PVC~18,400 LFAxtell + Birome

Proposed 12" PVC~11,000 LFMoore + Axtell +EOL + Prairie Hill+ Birome

Proposed GST0.5 MGAxtell + EOL +Moore + PH+ Birome

Proposed 8" PVC~15,800 LFEOL + Prairie Hill

Proposed 6" PVC~4,300 LFPrairie Hill

EOL/PHProposed 12" PVC~21,700 LFEOL + Prairie Hill

Proposed 8"~7,700 LFPrairie Hill

Proposed 8" PVC~5,000 LFAxtell + Moore+Birome

Proposed 6" PVC~4,300 LFMoore

Proposed 6" PVC~9,900 LFBirome

Arsenic Impacted AreaAxtell-EOL-Moore-Prairie Hill-BiromeAlternate Supply: City of Waco SW

LEGENDProposed Water Lines

6"8"12"

UtilityAXTELL WSCBIROME WSCE O L WSCLEROY TOURS GERALD WSCMOORE WATER SYSTEMPRAIRIE HILL WSC

ÜOrig. Size: 11"x17"

1 inch = 5,700 feet

S. Loop

340

Hwy 84

&

&

&

&

&

&&

&

&&

&

&

CITY OF RIESEL

M S WSC

H & H WSCH & H WSC

R M S WSC

CITY OF RIESEL

CITY OF RIESEL

M S WSC

H & H WSCH & H WSC

R M S WSC

CITY OF RIESELHwy 6

Proposed 12" PVC, ~26,800 LFShared: MS, RMS, City of Riesel, H&H

Proposed 6" PVC, ~7,800 LFCity of Riesel

Proposed 6" PVC, ~4,500 LFM.S. WSC

Proposed 8" PVC, ~13,200 LFShared: MS, RMS, City of Riesel

Proposed GST0.5 MG

S. Loop 340

LEGENDProposed Water Lines

6"8"12"

Coverage Area of City UtilityCITY OF RIESELH & H WSCM S WSC

Proposed GST0.2 MG

Proposed 6" PVC, ~4,100 LFShared: MS, RMS, City of Riesel

Proposed 8" PVC, ~40,000 LFShared: MS, RMS, City of Riesel

Proposed 6" PVC, ~7,800 LFCity of Riesel

Proposed 6" PVC, ~4,100 LFShared: MS, RMS, City of Riesel

Proposed 6" PVC, ~4,500 LFM.S. WSC

Alt. B: MS- RMS- City of Riesel Orig. Size: 11"x17"

Ü1 inch = 5,000 feetAlt. A: MS- RMS- City of Riesel- H&H

S. Loop 340

Proposed Layout Arsenic MitigationAlternate Supply: City of Waco SW

12

20

12

12

20

12

PURE WSC

LEROY TOURS GERALD WSC

LEROY TOURS GERALD WSC

MCLENNAN COUNTY WCID 2

Proposed 6" PVC33,300 LFLTGProposed GST

0.125 MGLTG

ÜOrig. Size: 11"x17"

1 inch = 2,000 feet

Arsenic Impacted AreaLeroy-Tours-Gerald

Alternate Supply: City of Waco SW