water quality index for agricultural runoff (wqiag) · water quality index for agricultural runoff...

Water Quality Index for Agricultural Runoff

(WQIag)By

Harbans Lal, Environmental EngineerNational Water Quality/Quantity Team, WNTSC/USDA-NRCS, Portland, OR

and

Brooks Engelhardt, Resource ConservationistUSDA-NRCS, Oxnard, CA

Water Quality Index for Agric. Runoff (WQIag)

Outline• Definition of an Index & its Common Uses• Complexity of Water Quality Parameters• WQI (Water Quality Index)

• WQIag (Water Quality I ndex for Agricultural Runoff)• Justification• Components • Description & Procedure• Demo

• Current and Potential Usages (Case Study from California by Brooks Engelhardt)

• Concluding Remarks and Future Plans

Helping People Help Land

Definition of Index

• A dimensionless number that combines multiple variables into a single value representing the overall condition (measure) of something

• Traditionally used for financial and other systems (Dow J, NASDAQ, Happiness Index, GDP Index, etc.)

• Easy to understand and follow

Indices and their General Usage

Livestock and Poultry Environmental Learning Center Webcast Series March 7, 2014

This presentation is archived at: http://www.extension.org/pages/21819/chronological-webcast-archive

Water Quality (WQ)

‐ A complex representation of multiple factors

‐ Includes parameters such as DO, pH, Turbidity, BOD, COD, Ecoli, Temp, Nutrients (N & P) and many more

‐ WQ Parameters expressed in different units (ppm, number, etc.) and measured in different ranges

‐ Hard to understand and follow by non‐professionals

Felt need for a simple tool for expressing WQ

WQI (Water Quality Index)

• Thus, the concept of the Water Quality Index (WQI) is introduced

• The concept is adopted by many state, national and international agencies including the US‐EPA, OR‐DEQ, India, Canada, FAO of the UN.

• How we got involved? A short story!

Water Quality Index (WQI)

‐ A dimensionless number that combines the values of multiple water quality factors such as DO, pH, BOD, COD, Ecoli, Temp, Nutrients (N & P), etc. into a single value by normalized subjective rating curves

‐ Primarily used for evaluating the quality of water in rivers, streams and lakes, etc.

‐ Multiple models (Review Paper)

‐ No Index for Agricultural Runoff Water



Review Paper


Agriculture Uses Major Portion of Freshwater

Agriculture is the Major Source of Freshwater Pollution

Agriculture Needs & Pollutes Water


USDA/NRCS spends big moneys on conservation programs for improving water quality from agricultural and forested area

NRCS always looking for tools for evaluating the effectiveness of its conservation programs

NRCS Programs for Improving and Maintaining water quality



Justification

Tools for evaluating effectiveness of conservation practices for improving water quality

• Available Tools• Planning and Assessment Tool (e.g. CPPE)• Modeling (CEAP, RUSLE2, etc.)• Edge of Field (EoF) Monitoring

Tools either too generic or too expensive

Needed a tool that uses site-specific information and multiple factors with least cost


• Thus, need for a Water Quality Index for Agricultural Runoff (WQIag) was recognized

• Got us started on this project with intensive literature review and consultation with multiple disciplinary experts`


Web‐basedWQIag

Water Quality Index for Agricultural Runoff (WQIag)



Water Quality Index for Agricultural Runoff (WQIag)

Web‐basedWQIag

What it is?• A tool for ranking runoff water from agricultural

fields (1 to 10): 10 being the best

• Simple and easy to use web-based system

• Uses multiple field characteristics and management factors

• Weighting for different factors for local preferences

• Site-specific weather data with the possibility of customization


Components

• Field physical /sensitivity factors• Nutrient management • Tillage management • Pest management• Irrigation / Drainage management• Conservation practices




Description & Procedure

• Multiple factors in some of the components

• Ranks and combines factors within a component

• Ranks and combines different components

• WQIag# based upon 4-key components

• Adjusting WQIag# based upon drainage/irrigation type

• Adjusting WQIag# based upon conservation practices

Demo

Current and Potential Uses


Use of the Runoff Water Quality Index in Ventura County, CA

Brooks Engelhardt

Resource Conservationist

USDA‐NRCS



WQI tool used to evaluate runoff in a citrus orchard located on sloped land in a Mediterranean Climate

Field location

Setting:‐mature lemon orchard‐ loam soil‐ 5%‐9% slopes‐minimal ground cover in the alleys‐micro‐sprinkler irrigation‐tree rows up and down slope

Field location

Field location

Resource Concerns:- sheet and rill erosion,

estimate soil loss = >6 tons/ac/yr. RUSLE2

- irrigation induced erosion- irrigation runoff-storm runoff, sediment transport

WQI benchmark = 5.67



Benchmark WQI output: 5.67

Selected “Medium Veg Cover,” Considers: tree canopy, shredded prunings on orchard floor“sprinkler irrigation” and “No till”

Soils data is from theWeb Soil Survey

Lemon orchard treated with cover crop

Planted: November, 2012

Cover crop growth in spring

March 2013 April 2013



RUSLE 2 ‐ estimated soil loss from sheet and rill erosion

Benchmark condition: >6 tons/ac/year

Planned condition (adding cover crop): <1 ton/ac/year

WQI output increased 5.67 to 5.85, changing to “High Veg. Cover”

WQI output increased to 7.30 Adding conservation cover (planting reseeding, cool season annual grasses)

Other Current and Potential UsesNRCS-National Water Quality

InitiativeIntegrated into “FieldPrint” Calculator of Field2Market

Baseline Criteria for Water Quality Trading

State WQIag WQIagwith Conservat-ion

WQIagTrend

Colorado 6.25 8.85 +2.6

Hawaii 5.08

Idaho 3.43

Indiana 5.92

Minnesota 7.1 8.19 +1.09

Oklahoma 5.26 6.88 +1.62

Possibility of Many More Applications and Usage

www.fieldtomarket.org



Concluding Remarks

• WQIag ‐‐ an index for quick assessment with least cost• Incorporates professional knowledge and local preferences through weighting factors

• Low cost, Low Rigor, High Intensity Usage Tool• Highly useful when actual monitoring is out of reach



Future Plans

• Re-designing nutrient management component and tile drainage system

• Extending WQIag framework at the whole farmand watershed level

• Working with the Idaho National Lab of the US-DOE) to link WQIag to their LEAF framework for evaluating water quality at landscape level

• Calibration with actual monitoring data and othermodels


Our MottoTo be innovative in solving

water problems

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