Comprehensive Watershed Comprehensive Watershed Management for - - PowerPoint PPT Presentation

Comprehensive Watershed Comprehensive Watershed Management for Central Arizona Management for Central Arizona Basins and the Valley of the Sun Basins and the Valley of the Sun

Acknowledgements

• Sponsors:
• Central Arizona Project
• City of Peoria
• In-Kind Contributors:
• Arizona Department of Environmental

Quality

• City of Tempe
• City of Scottsdale

Students

Leah Bymers (M.Sc.) Shelby Flint (M.Sc.) Chris Goforth (Ph.D) Emily Hirleman (Undergrad) Nick Paretti (M.Sc.) Chad King (Ph.D, Webmaster)

http://ag.arizona.edu/limnology/watersheds

New website

• ag.arizona.edu/limnology/watershed

Background

• Started examining watersheds

surrounding the Valley in 1996 (Lake Pleasant and the CAP Canal).

• Expanded to include Roosevelt,

Apache, Canyon, Saguaro, and Bartlett in 1999.

• Currently assessing watershed

health in all of the reservoirs surrounding the Valley including the Salt and Verde Rivers above and below them.

Rationale for a Watershed- Based Approach

• What are we really trying to

measure?

– “environmental health”, “ecological integrity”, “biologic potential” etc.

• How does this relate to drinking

water quality?

– Striving for “ecological integrity” inextricably brings us closer to “water quality” for municipal use.

Integrity Defined

• General definition: “a systems

ability to generate and maintain biotic elements through natural evolutionary processes.” (Karr 1994).

• Integrity refers more to a system’s

capacity and resilience than to its particular state.

Adopting integrity as a management goal does not imply maximizing any particular process rate (such as production) or compositional attribute (such as biodiversity); rather, it implies maximizing similarity to previously evolved ranges of states and process rates.

• Human impact on ecosystems

typically stems from changes in physical, chemical, or biological attributes and from more than one stressor (i.e. cumulative effects and synergy).

• Consequently, restoring ecological

integrity must be based on a broad, holistic perspective that recognizes myriad potential constraints.

• Water quality monitoring and

assessment has traditionally been compartmentalized by the requirements of specific technical disciplines and has typically been undertaken at the site scale.

• Determining what integrity is for an

ecosystem means gleaning from the data anthropogenic vs. natural stressors.

• Although natural systems may not

be completely restorable, what

• ften can be restored is a system’s

ability to generate and maintain ecological elements through natural evolutionary processes.

Values Assessment

• Management goals for watersheds

(e.g., exploitation, protection, restoration) are not selected by society scientifically, but are based

• n prevailing values.
• Scientists are rarely, if ever,

charged with choosing large-scale management goals.

• The role of science in watershed

management is:

– To describe past, present, or future ecosystem states. – Develop prescriptions for guiding ecosystems toward societal-preferred states. – Articulate the costs and benefits of maintaining ecosystems in selected states.

The integration of physical, chemical, biological, and socioeconomic expertise needed to protect or restore an ecosystem makes watershed management a truly multidisciplinary endeavor

Specific Goals

• Assessment

Assessment

– Determine current physical, chemical, and biological integrity of drainage basins to the Phoenix Valley.

• Prediction

Prediction

– Based on the above data, predict each watersheds long- and short-term sustainability in light of various stressors.

Goals (cont.)

• Recommendations

– Based on integration of all current and potential stressors, we will make recommendations to increase or sustain ecologic integrity (e.g., “water quality”).

Sampling/Research Design

• Watershed monitoring/data

acquisition should account for spatial and temporal variation.

• The watersheds surrounding the

Valley do not start with reservoir releases, the lowest reservoirs, or treatment plant intakes.

Spatial Variability in Reservoirs

Issues of Concern (e.g., “Stressors”

• Drought
• Eutrophication
• Rodeo-Chedeski Fire (and potential

for other wildfires)

• Population Growth
• Perchlorate
• Algal Toxins
• Disinfection by-products

Drought

• Despite recent precipitation events,

hydrological drought persists in the southwest.

• Recent precipitation may bring

short-term relief.

• Water year precipitation is still

below average for most of the southwest.

• Since January, there have been

increases in precipitation and percent of average snow water content.

• However, snowpack is/was still quite

low in Arizona.

• Seasonal forecasts indicate an

increased probability of above average temperatures across Arizona and New Mexico throughout the spring and summer.

• There is a slightly better-than-

average chance of a weak El Nino episode developing during the second half of 2004.

Long-Term Climate Forecast

• Unlike El Nino/La Nina events, which

usually last from 6-18 months, Pacific Decadal Oscillations (PDO) can last 20-30 years.

• Positive PDO phase = colder water

in the North Pacific driving the jet stream well to the North of Arizona.

• Negative PDO phase = warmer

water in the North Pacific enhancing the jet stream over Arizona.

Climate Summary

• Possible short-term drought relief

due to El Nino events.

• Long-term drought may continue

due to positive PDO phase.

Drought Effects on Reservoir Water Quality

• Warmer than normal temperatures

earlier in the spring may lead to an earlier onset of thermal stratification.

• Prolonged stratification usually

results in prolonged hypolimnetic anoxia.

• Earlier than normal algal blooms

may exacerbate thermal stratification.

• Increased strength of stratification,

and subsequent hypolimnetic anoxia, may mean bioavailable nutrients released from sediments and into downstream reservoirs, rivers or canals

• Sediment nutrient release may

result in increases in primary production which may lead to increased strength of stratification which means more nutrients released from sediments etc. initiating a positive feedback mechanism.

• Decreased residence time in the

reservoirs, may exacerbate the possible increases in primary production.

• Water quality problems associated

with drought include increases in;

– Disinfection by-products – Algal toxins – Tastes and odors – Salinity/TDS/Conductivity

http://www.rangeview.arizona.edu

Geospatial Tools for Natural Resource Management

Drought, Wildfire, and Water Quality; The Rodeo- Chedeski Fire and Impacts

• n Roosevelt and Beyond

• As stated during the last meeting,

the water quality effects on the Salt River and reservoirs below it from the Rodeo-Chedeski fire will be subtle and will occur in pulses.

91202 120302 30603 52903 81903 121703 30804 Date 2000 4000 6000 8000 10000 12000 14000 16000

Overlay Chart

Y Mean(Flow_cfs) Mean(Turbidity_NTU)

Chart

91202 120302 30603 52903 81903 121703 Date 5 10 15 20 25 30 35 Y Mean(NH3-N (ppm)) Mean(NO3+NO2-N (ppm Mean(Total P (ppm)) Mean(TKN (ppm))

Heavy nutrient loading following monsoon rains over burn area

But are present conditions different than post-fire conditions?

71999 82399 92799 110299 20800 50900 500 1000 1500 2000 2500 3000 3500 4000 Mean(Flow_cfs)

91202 81903 121703 30804 500 1000 1500 2000 2500 3000 3500 4000 Mean(Flow_cfs) 120302 30603 52903

Pre- and Post-Fire Nutrient Loading

Post Pre Pre/Post Fire .0 .5 1.0 1.5 2.0 2.5 3.0 Y Y Mean(NH3-N (ppm)) Mean(NO3+NO2-N (ppm Mean(Total P (ppm)) Mean(TKN (ppm))

• The detrimental effect of the pulses
• f suspended solids, nutrients, and
• ther pollutants on the Salt River

itself are relatively short-lived and will decrease over time.

• However, the detrimental effect on

Roosevelt and downstream reservoirs will probably be longer- lived.

Pre- and Post-Fire Data from Roosevelt

Post-Fire Pre-Fire Pre/Post Fire 1 2 3 4 5 6 7 8 9 10 11 Mean(Chl a (mg/m3))

Chart

Nutrients

SRROOA SRROOB SRROOC SRROOA SRROOB SRROOC Post-Fire Pre-Fire Site by Pre/Post Fire .00 .05 .10 .15 .20 Y Y Mean(Total P (mg/L)) Mean(Nitrate+Nitrite-N (mg/L Mean(Ammonia-N (mg/L))

SRROOA SRROOB SRROOC SRROOA SRROOB SRROOC Post-Fire Pre-Fire Site by Pre/Post Fire 1 2 3 4 5 6 7 8 Y Y Mean(TOC (mg/L)) Mean(DOC (mg/L))

TOC/DOC

Trophic State Change Pre- and Post-Fire

Pre-Fire

Components: Total N (mg/L) Total P (mg/L) Chl a (mg/m3) Ammonia-N (mg/L) Nitrate+Nitrite-N (mg/L) Prin Comp 1 Prin Comp 2 Prin Comp 3 Prin Comp 4 Prin Comp 5 Total N Total P Chl a ( Ammonia Nitrate x y z 2.1809 1.5404 0.6854 0.5933

• 0.0000

EigenValue 43.618 30.808 13.708 11.866

• 0.000

Percent 43.618 74.426 88.134 100.000 100.000 Cum Percent Total N (mg/L) Total P (mg/L) Chl a (mg/m3) Ammonia-N (mg/L) Nitrate+Nitrite-N (mg/L) Eigenvectors 0.65931

• 0.28956

0.27899 0.56096 0 29823 0.01028 0.48265 0.54587

• 0.34800

0 58981 0.13307 0.75836 0.09894 0.43061

• 0 46040

0.25863 0.32878

• 0.78384

0.01167 0 45878

• 0.69326

0.00000 0.00000 0.61535 0 37516

Principal Components Spinning Plot

Post-Fire

Components: Total P (mg/L) Total N Chl a (mg/m3) Ammonia-N (mg/L) Nitrate+Nitrite-N (mg/L) Prin Comp 1 Prin Comp 2 Prin Comp 3 Prin Comp 4 Prin Comp 5 Total P Total N Chl a ( Ammonia Nitrate x y z 1.9932 1.2380 0.9528 0.6614 0.1546 EigenValue 39.864 24.761 19.055 13.228 3.092 Percent 39.864 64.625 83.680 96.908 100.000 Cum Percent Total P (mg/L) Total N Chl a (mg/m3) Ammonia-N (mg/L) Nitrate+Nitrite-N (mg/L) Eigenvectors

• 0.24002

0.61277 0.64158 0.39299 0.02887 0.00471 0.33665

• 0.05384
• 0.49295

0.80047 0.95491 0.12259 0.26204

• 0.03140
• 0.05889

0.15152

• 0.19989
• 0.24585

0.76603 0.53838

• 0.08693
• 0.67542

0.67555

• 0.12157

0.25514

Principal Components Spinning Plot

• Pre-fire trophic status =

43.143 or mesotrophic

• Post-Fire trophic status =

58.913 or eutrophic

TSI calculated using Kratzer & Brezonik, 1981

Summary

• Probable continued drought.
• The Salt River reservoirs continuing

to feel effects of Rodeo-Chedeski fire.

• Nutrient in-loading in Roosevelt

may increase trophic status of downstream reservoirs.

• Earlier than normal onset of high

temperatures may increase, and prolong, thermal stratification and hypolimnetic anoxia.

Questions?