Hydrologic Elements of the Taos Valley

Settlement

John Shomaker

John Shomaker & Associates

Albuquerque

March 4, 2017

Technical Goals of the Settlement

• Protect acequias from depletion of flows due to future groundwater

development. “Nurture acequia irrigation.”

• Limit attrition of acequia acreage by transfers of acequia water rights

to support future groundwater development.

• Protect the Buffalo Pasture wetlands from depletion and shrinkage due

to future groundwater development.

• Provide some additional storage.

and at the same time…

• Provide a means for groundwater development to support population

and economic growth.

• Protect the Rio Grande hydrologic system from additional depletions

caused by future groundwater development.

John Shomaker & Associates, Inc.

Participating Members of Taos Technical Committee

Names From Party Represented

Peggy Barroll

Peter Burck

NM Office of the State Engineer (OSE) State of New Mexico

Robert Talbot

Tom Bellinger

US Bureau of Reclamation (USBOR) United States

Lee Wilson (Chair)

Roger Miller

Lee Wilson and Associates Taos Pueblo

Mustafa Chudnoff

Jay Lazarus

Meghan Hodgins

Paul Drakos

Glorieta Geoscience Town of Taos

John Shomaker John Shomaker and Associates, Inc. Taos Valley Acequia Association

Maryann Wasiolek

Michael Spinks

Hydroscience Associates Inc. El Prado Water and Sanitation

District

Chris Banet

Bill White

John Sandoval

US Bureau of Indian Affairs (USBIA) Taos Pueblo

Barroll presentation, Taos Settlement Technical Work, Oct. 8, 2013

John Shomaker & Associates, Inc.

Barroll, P., and Burck, P., 2006. Documentation of OSE Taos area calibrated groundwater flow model T17.0: New Mexico Office of the State Engineer.

Key references and final T17.0 model report

Drakos et al.,

2004a

Aquifer Compartmentalization

Several of the intrabasin faults act as hydrologic boundaries, and

result in some compartmentalization of the deep basin-fill aquifer. The Seco

fault acts as an impermeable boundary, and may act to separate a northeast

deeper aquifer system that has been recharged by modern to Holocene

precipitation separated from a southwest deep aquifer system that has been

recharged by older, possibly Pleistocene precipitation (Drakos et al., this

volume). Data from high-precision temperature logs also indicates

compartmentalization of the deep basin fill aquifer (Reiter and Sandoval, this

volume). Some Los Cordovas fault splays act as impermeable boundaries (e.g.

the eastern Los Cordovas fault near BOR1 and one or both of Los Cordovas

faults near RP2500), whereas other faults do not appear to affect groundwater

flow in the deep aquifer (e.g. the western Los Cordovas fault near the Airport

well and near UNM/Taos). This may indicate variable cementation along the

fault plane and/or variable offset along Los Cordovas fault strands.

Drakos et al., 2004a

Drakos et al.,

2004b

The goals can be met by taking advantage of the local

groundwater conditions…

• Town of Taos and El Prado WSD will limit groundwater

pumping from near the Buffalo Pasture, and future pumping will

be from deep wells farther to the west.

• Deep “mitigation wells” will be used to offset depletion of streams

that supply acequias.

• The Buffalo Pasture recharge project will support the wetland,

and offset the effects of future pumping.

so that…

• The effects of pumping on streamflow will occur on the main

stem of the Rio Grande, not in the local tributary streams, and

can be offset with Rio Grande water rights and SJCP water.

John Shomaker & Associates, Inc.

The Local Groundwater Conditions…

Geologic Background

Groundwater Flow• shallow groundwater and surface streams closely related

• downward flow from layer to layer

• discharge to Rio Grande from lower layers

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Cross-Section from Mountains to Rio Grande

Barroll and Burck, OSE, Attachment 3

Cross-Section Showing Groundwater Flow

Groundwater Flow Model, to Calculate Drawdown and

Stream Depletion

Purpose: account for natural geological conditions and historical

flows and pumping, and predict future effects

Authors: Barroll and Burck (OSE), with committee from parties

to settlement

Elements:

7 layers, representing major geologic units

Rio Grande and 6 tributaries

Buffalo Pasture and other evapotranspiration

municipal and other public-supply wells

recharge from precipitation

recharge from streams and irrigation return flow

discharge to Rio Grande and tributaries

Calibration: matching water-level measurements with model

simulation

Provision for model updates: any party can propose an update (Sec. 7.2)

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Taos Valley

Groundwater Model

Taos

ASR wells

mitigation wells

streams, Buffalo Pasture

existing and proposed wells

John Shomaker &

Associates, Inc.

Cross-Section Showing Groundwater Flow and Wells

public-supplyor Puebloproductionwell

ASR, mitigationwell

New Public-Supply and Pueblo Wells

• Deep, and closer to Rio Grande to shift effects

away from shallow aquifer and local streams.

• Locations shown on Attachment 10.

John Shomaker & Associates, Inc.

Additional Storage in the System…

Aquifer Storage and Recovery Project

• excess Rio Lucero flows that now go to Rio Grande without

being used, stored for summer use.

• pipeline (or lined ditch) from Rio Lucero diversion to

minimize conveyance losses, 18.3% of total flow.

• 100 ac-ft/yr depletion, 260 ac-ft/yr diversion and

recovery (327 gpm for 6 months).

• acquire 100 ac-ft/yr existing water rights, to keep Rio

Grande whole.

• ASR wells completed deep in aquifer (1,000 ft) to avoid

affecting shallow wells; test well and analysis first.

• filter and treat to drinking-water standards before

injecting and recovering.

• alternative surface storage if ASR isn’t feasible.

John Shomaker & Associates, Inc.

Conceptual Schematic, ASR Project

Acequia Madre del Rio Lucero y del Arroyo Seco

existing diversion

Pipeline or lined ditch

diversion and pump for ASRASR wells

excess flow to inject inASR wells

summer flowfrom ASR

John Shomaker & Associates, Inc.

Conceptual Layout of ASR

Treatment Facility (90’ x 140’)

Bruce M. Thomson, Ph.D., P.E.

Alternatives…

• ASR project

• Surface storage project (260 ac-ft)

• Land available?

• Evaporation and seepage loss.

• No additional storage.

John Shomaker & Associates, Inc.

Mitigation Wells

• To offset depletion of streams (and the water available

to acequias) due to new pumping allowed

under Settlement:

Rio Grande del Rancho

Rio Chiquito

Rio Fernando de Taos

Rio Lucero – Rio Pueblo de Taos

Rio Hondo

• Pumping from mitigation wells limited to model-calculated

depletion effects each year ( to preserve the current

condition, not add to anybody’s supply).

• Wells pump from deep in aquifer (800-1,000 ft), to shift

effects from local streams to Rio Grande.

• Wells operated by Town or MDWCA, also available

to produce under their water rights if desired.

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Mitigation well construction and testing

• No drainage of shallow aquifer into deeper zones.

• Geophysical logs and samples used to identify

low-permeability zones.

• Casing cemented into top of deep producing

interval below a low-permeability zone.

• No mixing of shallow and deep groundwater because

of cement seal.

• No discharge of water that would not meet NMED

discharge standards.

• Water samples collected before well is completed.

• Water sampled and analyzed during pumping tests.

• Water sampled during operation as required by NMED.

John Shomaker & Associates, Inc.

Shallow aquifer (layers 1-3)cement

8-5/8 or 12-in. casing

well screen

filter pack

Deeper aquifer (layers 5-7)

Conceptual well configuration (not to scale)

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Mitigation well costs…

• Drilling, testing, water analyses, pump, surface

equipment, etc., paid as part of Settlement.

• Operation (pumping, water analyses, water

treatment, maintenance, replacement) paid by

applicant for a new groundwater supply, not by

acequia or MDWCA.

Pumping from mitigation wells would be small…

Stream depletion due to projected new pumping by

Taos, El Prado, and Pueblo, to be offset by pumping

from mitigation wells

Stream (depletion offset by pumping

from mitigation well)

Modeled annual pumping, ac-ft

Year 40 Year 100

Rio Hondo 94 155

Rio Lucero, Rio Pueblo 154 183

Rio Fernando 113 142

Rio Grande del Rancho 175 219

Rio Chiquito 28 35

Arroyo Seco (ASR wells?) 7 11

John Shomaker & Associates, Inc.

Alternatives—• Mitigation wells to provide water to offset new depletions.

• Limit future development to supplies available under

existing groundwater rights.

• Continue to lose irrigated lands under acequias

as rights are transferred out (CU = 1.38 ac-ft/ac).

John Shomaker & Associates, Inc.

Acequias on…

Modeled annual pumping for offsets

at 40 years, ac-ft

Acres retired by 40 years from now if

no mitigation pumping

Rio Hondo 94 68

Rio Lucero, Rio Pueblo 154 112

Rio Fernando 113 82

Rio Grande del Rancho 175 127

Rio Chiquito 28 20

Arroyo Seco 7 5

• If new supply wells for Taos, Taos Pueblo, and El Prado

tap the shallow aquifer closer to the mountains, rather

than the deep aquifers as in the Settlement...

• The necessary offsetting rights would be much

greater, and

• The acequia acreage retired would be

correspondingly greater.

John Shomaker & Associates, Inc

Taos Settlement: Domestic Wells

• Total shallow-aquifer drawdowns associated with all groundwater pumping under Settlement are less than 10 feet after 40 years.

• Protection of flows in streams and the acequia system helps maintain shallow-aquifer recharge.

John Shomaker & Associates, Inc.