Technical Evaluation of Reports by U.S. Environmental Protection Agency on Nitrate in Water Wells in the Yakima River Basin, Yakima

County, Washington2015 Waste To Worth Conference

Seattle, Washington

Jay Lazarus and Elke Naumburg, PhDGlorieta Geoscience, Inc.

PO Box 5727Santa Fe, NM 87502

(505) 983-5446www.glorietageo.com

Purpose and Scope• Technical evaluation of 3 reports prepared by Region

10 EPA Staff• Evaluation funded by the Washington State Dairy

Federation and Dairy Producers of New Mexico• Relation between Nitrate in Water Wells and Potential

Sources in the Lower Yakima Valley, Washington, EPA-910-R-12-003, September, 2012 (Report)

• Quality Assurance Project Plan, Yakima Basin Nitrate Study Phase 2 – Initial Nitrate/Coliform Screening of Domestic Wells February 2010 Sampling Event, Yakima County, Washington, U.S. EPA Region 10, January 27, 2010 (QAPP2)

• Quality Assurance Project Plan For Yakima Basin Nitrate Study Phase 3 – Comprehensive Analytical Source Tracer Sampling April 2010 Sampling Event, Yakima County, Washington, U.S. EPA Region 10, April 27, 2010 (QAPP3)

Purpose and Scope

This presentation will address how to accurately characterize the

hydrogeology below dairy production areas and land application fields, and how to proactively manage nutrients

Groundwater & Nitrate

Challenge: Complex Setting

Common challenge: multiple sources of nitrate are intermingled:• Dairies• Farm fields with chemical/organic

fertilizers• Orchards with chemical/organic

fertilizers• Homes with septic systemsNew Mexico

Washington

Challenge: Complex Setting

• Hypothetical example: • What is the source of or

pathway for nitrate in the monitoring location?o Neighbor’s improperly

installed/maintained septic system?o Improperly completed wells providing

conduits to ground water?o Farmland upgradient from dairy?o Farmland where farmer over-applies

commercial fertilizer?o Farmland where farmer uses manure

obtained from dairy?o Orchards?

• How would you determine this?

Challenge: Monitoring Wells• Additional challenges in Yakima:

o Few to no monitoring wells presento Existing wells (irrigation & domestic) are completed at a range of depthso Completion information (depth, screen depth) for many existing wells is

unavailable

Location of monitoring wells in Yakima Valley, Source: Dept. of Ecology

Source Tracking• In Yakima, EPA focused on groundwater

chemistry, assuming that indicators such as pesticides and other trace organic compounds would tie the groundwater nitrate to a specific source.

• However, organics behave very differently from the highly mobile nitrate…

• Aquifer characteristics and sampling well completion information were not fully assessed but directly affect the movement of nitrate in groundwater and

• Thus, the choice of study design prevented conclusive results.

Regional Hydrogeology

Because none of the potential sources are isolated, source tracking requires an in-depth knowledge of aquifer properties such as• Groundwater flow direction• Aquifer thickness• Hydraulic conductivity• Vertical leakanceIn addition, need to understand localized effects of• Ditches/drains and • Production wells on groundwater flow

Regional Hydrogeology

• The Yakima Valley is underlain by 3 aquifers:o a shallow perched aquifer likely related to irrigation

return flows,o an alluvial aquifer o an underlying basalt aquifer with interbedded sands

• The 3 aquifers are hydrologically connected either through natural pathways or through wells completed into more than one aquifer.

• Depths and screen intervals were known for about a third of the wells sampled by EPA.

Regional Hydrogeology

Source Tracking• Better study design:• Use monitoring wells or

existing wells with completion information to characterize the aquifer and groundwater flow direction in particular

Source Tracking• Source tracking with aquifer

knowledge - still have multiple potential upgradient sources

• Need:o Upgradient monitoring wellso Monitoring wells downgradient

from potential sources

Proper Monitoring Well Completion

• Casing extends above ground surface and is protected by a large concrete pad and bollards

• Concrete pad sloped away from well

• Monitoring well is locked

• Screen straddles the top of the water table

EPA’s Improper Monitoring Well Surface Completion

• Well is located in bar ditch – a depression where water will accumulate

• Water will accumulate around well head

• No well surface pad • This type of well head

completion is for urban/gasoline/chlorinated hydrocarbon type monitoring on asphalt or concrete – not agricultural

Improper Monitoring Well Surface Completion

Improper Monitoring Well Surface Completion

Sampling DesignIt is crucial for any study examining nitrate sources to have knowledge about:• Well completion information• Depth, degree of interconnectedness, and

extent of aquifers• Groundwater flow direction• Aquifer parameters (k, S or Sy, T)

If this information is not available, potential source identification or pathways cannot be

accurately determined.

Sampling DesignAnalytical methods that have been employed are:• Relationship between chloride and nitrate-N

concentration:o Synthetic fertilizer has little to no chlorideo Dairy lagoons tend to have high chloride concentrationso Septic systems tend to have intermediate concentrationso Complicating factors

• Sources overlap• Different geochemistry of source water

o Shallow ground watero Deeper ground watero Surface water sources

Chloride vs. Nitrate-N

McQuillan, 2004

Sampling DesignMethods that have been employed are:• Relationship between chloride and nitrate-N• Nitrogen and oxygen isotopes:

o Synthetic nitrate fertilizer has lower d15N values than organic sources

o Synthetic nitrate fertilizer has higher d18O than organic sources

o Problem – nitrogen may undergo numerous biological transformations, which change the isotopic signature detected in groundwater

o Problem – sources overlapo Problem – greenwater has a wide range of 15N so the

nitrogen isotope analysis requires a dairy-specific approach

Nitrogen and Oxygen Isotopes

Kendall, 2004, USGS

Sampling DesignData sets that have been used to distinguish different different sources of nitrate in groundwater:• Relationship between chloride and nitrate-N :• Nitrogen and oxygen isotopes:• Isotopes in water:

o Water in lagoons evaporates, enriching the lagoon and groundwater beneath if the lagoon is leaking significantly

• Boron isotopes:o Boron is present in detergents and fertilizers – both have

unique range of d11B

Isotopes in Water

-110

-100

-90

-80

-70

-60

-50

-13 -12 -11 -10 -9 -8 -7

d 18O, o/oo

d 2 H

, o/o

o

Global MWL (Craig, 1961) Dairy 1 Dairy 2 Dairy 3 Dairy 4

Downgradient from lagoon – falls well below MWLUpgradient from

lagoon – falls close to MWL

-5 0 5 10 15 20 25 300

2

4

6

8

10

12

14

MW- BaselineMW- Land Application AreaMW- LagoonMW- Flood IrrigationLagoonManureFertilizer

δ15N (‰)

δ1

8O

(‰

)

Dairy Area IsotopesDowngradient from corral, near pecan flood irrigation

Nutrient Management• Manage nutrients to insure nitrogen in applied

at agronomic rates• By maintaining agronomic rates, nitrogen will

not leach beneath the root zone• Sample irrigation and other production wells as

part of nitrogen loading calculations• Maintaining good ground water quality and soil

health retains the value of the CAFO facility for future generations

• Informed decision lead to optimal use at the CAFO, insuring “wastes” are converted to assets or worth

Dairy Sampling, Monitoring & Reporting with CAFOweb™

integrationSampling: (Performed by consultants and/or Dairy)

Monitoring wellsLagoonSoilsManurePlant tissue

Laboratory Analysis

Consultants and/or Dairymen

Lab Report

Monitoring:(Data collected by Dairy and/or consultants)

Effluent meter readingsCrop planting & harvestingCrop IrrigationRecord Keeping

Track Data Trends in Reports:Discharge, MW, Lagoon, Soils, Manure, Yields, Irrigation, Nitrogen application

Predict:Effluent & manure solids applicationFertilizer applicationFreshwater application

Data Entry

Case Study:Nitrogen Tracking

Conclusions• Overall the Report provides a significant lack of supporting technical

information for EPA to arrive at the conclusions presented in the report.

• Locally the ground water flow direction may be modified by geologic structures and by irrigation practices, drains, ditches, canals, and other hydrologic features.

• Very limited data on well completion, screened intervals, pump setting, casing diameter, presence or absence of surface/sanitary seals is presented.

• Lack of well completion information severely limits EPA’s ability to verify if the wells identified as upgradient and downgradient of potential sources produce water from the same water bearing zone.

• No water levels were measured and converted to ground water elevations with which to construct seasonal potentiometric surface maps in each aquifer to determine temporal changes in both localized and valley-wide ground water flow directions.

• The dairies and other sites are located in a matrix of farming and septic systems, which makes source tracking impossible without detailed knowledge of aquifer and well properties.

• EPA did not produce enforcement-quality data from this study.

Always Know Where the Recharge Originates

Questions/DiscussionGlorieta Geoscience, Inc.

PO Box 5727Santa Fe, NM 87502

(505) 983-5446www.glorietageo.com