Transcript Salt & Selenium Presentation by Josh Linard

Salt and Selenium in Grand Valley
Rivers and Streams
Joshua Linard
U.S. Geological Survey Hydrologist
[email protected]
Presentation Outline
• Importance of salt and selenium
• Environmental processes controlling the movement
of salt and selenium
• Water-quality standards for salt and selenium
• Salt and selenium in the Colorado River
• Salt and selenium in Grand Valley tributaries
• Concentration vs. load
• Control initiatives
• Current investigations
What are Salt and Selenium?
• Salt
– Total Dissolved Solids: the mass of all cations and
anions in an aqueous solution
• Selenium
– A naturally occurring trace element
• It’s essential to life, but in excess can be harmful
Why Study Salt and Selenium?
•
High salinity water
– Clogs and corrodes household pipes and fixtures
– Limits agricultural productivity
• High selenium in water
– Limits reproductive ability and can even be fatal to biological
organisms
– Colorado Pike Minnow, Razor Back Sucker, Boney Tail Chub, Hump
Back Chub
Spatial Distribution of Mancos Shale
Tributary Stream
Environmental Processes
Sources of Water
• Average annual precipitation: 8 in/yr
• Canals
• Irrigation: 11-70 in/yr
– Residential areas
– Agricultural areas
Concentration vs Load
• Seasonality in salt and selenium are, generally,
explored in units of …
– Concentration
• Units of mass/volume
– Load
• Units of mass/time
– Salinity: tons/day
– Selenium: lbs/day
Water-Quality Standards
• Standards focus on concentrations
• Colorado Department of Health and Environment
– Salinity
• Established in 1976 for the entire Colorado River Basin
• Flow-weighted annual values shouldn’t exceed 723 mg/l (ppm)
below Hoover Dam
– Selenium
• The water-quality standards are the 85th percentile for
the most recent 5 year period
– If 100 samples are available, 85 must be below the standard
• Established in 2000
• Acute = 18.4 μg/l (ppb)
• Chronic = 4.6 μg/l (ppb)
Water-Quality Standards for Salinity
and the Grand Valley
• Salinity standard at Hoover Dam: 723 mg/L
Stream Gage
Mean-Daily Salinity
Concentration (mg/L)
Colorado River near Cameo, CO
368
Gunnison River near Grand Junction, CO
786
Colorado River near Colorado-Utah State Line
604
Persigo Wash at River Road
2,063
Water-Quality Standards for Selenium
and the Grand Valley
• CDPHE chronic standard for selenium: 4.6 μg/L
Stream Gage
Mean-Daily Selenium
Concentration (μg/L)
Colorado River near Cameo, CO
0.6
Gunnison River near Grand Junction, CO
4.5
Colorado River near Colorado-Utah State Line
4.0
Persigo Wash at River Road
35.5
Why are concentrations so much higher in
tributaries than in the Colorado River?
• Seasonal changes in the availability of water
effect the amount of salt and selenium in
streams
– The Colorado River has more water to dilute
tributary inputs of salt and selenium
– Tributary water has more interaction with the
Mancos Shale in the Grand Valley
Leib, K.J. 2008. Concentrations and Loads of Selenium in Selected Tributaries
to the Colorado River in the Grand Valley, Western Colorado, 2004-2006. U.S.
Geological Survey Scientific Investigations Report 2008-5036.
Concentration and Load vs Streamflow
• Relationships to streamflow are general
• At a particular point, as flow increases the load
increases and concentration decreases
• Vary between salt and selenium
• Vary from place to place
Concentration and Load vs Streamflow
January
January
Concentration
Concentration
Streamflow
Streamflow
March
May
July
September November
January
January
March
May
Load
Load
Streamflow
Streamflow
March
May
July
September November
January
January
March
May
July
September
November
July
September
November
Concentrations and Loads of Salt and Selenium
Measured at the Colorado River near ColoradoUtah State Line
Salt Concentration Compared to
Streamflow
Non-irrigation Season
10
Irrigation Season
9.5
9
8.5
8
7
7.5
8
8.5
9
9.5
10
10.5
11
Streamflow (ln(cfs))
Salt Concentration (mg/L)
Salt Load (ln(tons/day))
Salt Load Compared to Streamflow
1200
1000
800
600
400
200
0
Selenium Load (ug/L)
Selenium Load (ln(lbs/day))
5
4.5
4
3.5
8
8.5
9
9.5
Streamflow (ln(cfs))
8
8.5
9
9.5
10
10.5
11
Selenium Load Compared to
Streamflow
Irrigation Season
7.5
7.5
Streamflow (ln(cfs))
Non-irrigation Season
7
Irrigation Season
7
Selenium Load Compared to
Streamflow
5.5
Non-irrigation Season
10
10.5
11
14
12
10
8
6
4
2
0
-2 7
Non-irrigation Season
Irrigation Season
7.5
8
8.5
9
9.5
Streamflow (ln(cfs))
10
10.5
11
Concentrations and Loads of Salt and Selenium
Measured at Persigo Wash at River Road
5.5
Salt Concentration Compared to
Streamflow
Non-irrigation Season
5
Irrigation Season
4.5
4
3.5
3
0
1
2
3
4
5
Salt Concentration (mg/L)
Salt Load (ln(tons/day))
Salt Load Compared to Streamflow
5000
4500
4000
3500
3000
2500
2000
1500
1000
500
0
Irrigation Season
Non-irrigation Season
0
1
Streamflow (ln(cfs))
2
3
Streamflow (ln(cfs))
4
5
Selenium Concentration (ug/L)
Selenium Load (ln(lbs/day))
Non-irrigation Season
1
4
5
Selenium Concentration Compared to
Streamflow
Irrigation Season
0
3
Streamflow (ln(cfs))
Selenium Load Compared to
Streamflow
2.5
2
1.5
1
0.5
0
-0.5
-1
2
100
Irrigation Season
80
Non-irrigation Season
60
40
20
0
0
1
2
3
Streamflow (ln(cfs))
4
5
Salt and Selenium Control
• Management options
– Increase flow to dilute salt and selenium
• Not really an option in the arid environment
– Decrease load to lower concentrations
• Control initiatives are aimed at minimizing loads
– Minimize source loads
– Decreases tributary loads
– Decreases concentrations in the Colorado River
Methods to Control Salt and
Selenium
• Irrigation delivery system improvements
– Lining and piping of canals and laterals
• Irrigation system improvements
– Sprinklers, drips, micro, etc.
• Best Management Practices for residential areas
• Line Ponds
• Indirect effects from land-use change and
population growth
Effects of Land-use Change on Source
Loads
1. Quantify irrigation water use and deep percolation
in representative areas where agricultural land has
been converted to suburban use.
2. Compare irrigation water use and deep percolation
at similar agricultural and suburban sites in the
Grand Valley.
3. Quantify deep percolation from pond seepage for a
selected number of ponds.
From Mayo, J.W. 2008. Estimating the effects of conversion of agricultural land to
urban land on deep percolation of irrigation water in the Grand Valley, Western
Colorado. U.S. Geological Survey Scientific Investigations Report 2008-5086.
Grand Valley Sites
• 14 Homes
• 4 Gated-Pipe Fields
• 3 Ponds
• 2 CSU Weather
Stations
Explanation
Homes &
Fields
Weather
Stations
Ponds
• Monitored for 2
irrigation seasons
(2005 & 2006)
22
Typical Residential Sites
¼-Acre Subdivision - bluegrass
5-Acre Estate - bluegrass
5-Acre Estate - Native Plants
5-Acre Estate – Orchard Grass
23
Typical Gated Pipe Sites
Quail Run – orchard grass
CSU – orchard grass
24
Typical Pond Sites
Paradise Hills Pond
Chipeta Pines Pond
25
Irrigation Water Use and Deep Percolation
(average acre-feet of water per acre for irrigation season)
Subdivision
Lots
(bluegrass) 1
n=10
Irrigation
Water Use
5 Acre
Estates
5 Acre
Estates
(bluegrass)
n=7
2
(native,
orchard
grass) 2
n=3
Gated Pipe
Fields
(orchard
grass) 3
n=4
NRCS
Alfalfa
Sites 3
Irrigation
Holding
Ponds 4
n=67
n=4
n/a
1.1
0.9
0.3
1.5
3.8
(ac-ft/ac)
(0.8 – 1.2)5
(0.8 – 1.3)
(0.1 – 0.9)
(0.6 – 2.7)
(1.6 – 5.8)
Deep
Percolation
0.14
0.08
0.0
0.6
1.27
9.55
(0.00 – 0.42)
(0.01 – 0.17)
(0.0 – 0.04)
(0.0 – 1.5)
(0.0 – 3.3)
(8.2 – 11.8)
(ac-ft/ac)
1 Acreage
for ¼ acre subdivisions in study was 40 percent irrigated on average
2 Acreage
for 5 acre estates in study was 32 percent irrigated on average
3
Acreage for gated-pipe and alfalfa sites was assumed to be 90 percent irrigated
4
Acreage for irrigation holding ponds was assumed to be 100 percent covered with water
5
Numbers in parentheses are the range of values
26
Salt Loading
(tons per acre per year)
• NRCS salt-loading factor for the Grand Valley is 4.1 tons per acre-foot
of water applied, with an estimated 50 percent of the load reaching the
Colorado River.
5 Acre
Estates
Gated Pipe
Fields
(bluegrass)
n=7
(native,
orchard grass)
n=3
(orchard
grass)
n=4
0.17
0.0
1.37
Subdivision
Lots
5 Acre
Estates
(bluegrass)
n=10
0.28
NRCS
Alfalfa Sites
n=67
2.89
Irrigation
Holding
Ponds
n=4
19.6
27
Can we see the effects of their implementation
in the water-quality of the streams?
From 1986 to 2003 the salinity load measured at
the Colorado-Utah Stateline has decreased by
over 300,000 tons.
Stream Gage
1986-2003
Colorado River near Cameo, CO
-193,000
Gunnison River near Grand Junction, CO
-202,000
Colorado River near Colorado-Utah State Line
-322,000
Butler, D.L., 1996, Trend analysis of selected water-quality data associated with
salinity-control projects in the Grand Valley, in the Lower Gunnison River Basin, and at
Meeker Dome, Western Colorado: U.S. Geological Survey Water-Resources
Investigations Report 95-4274, 38 p.
Bauch, N.J., and Spahr, N.E., 1998, Salinity Trends in Surface Waters of the Upper
Colorado River Basin, Colorado: Journal of Environmental Quality, v. 27, no. 3, p. 640655.
Leib, K.J. and Bauch, N.J., 2007, Salinity trends in the Upper Colorado River Basin
upstream from the Grand Valley Salinity Control Unit, Colorado, 1986-2003, U.S.
Geological Survey Scientific Investigations Report 2007-5288.
Summary
• Underlying geology is the source of salt and selenium
– Ground water transports salt and selenium to the
rivers and streams in the Grand Valley
• Water-quality at the Colorado-Utah State Line meets
standards
• Concentrations and Loads vary
– Seasonally
– Between salt and selenium
– Place to place
Summary
• Minimizing source loads in tributaries of the Grand
Valley, minimizes concentrations in the Colorado
River
• Controlling sources of salt and selenium
– Irrigation practices
– Best management practices
– Land-use
• Conversion from previously irrigated land to
residential reduces source loading
• Long-term trends indicate control initiatives are
working
Websites:
http://co.water.usgs.gov/index.html
http://waterdata.usgs.gov/co/nwis/rt/
http://rmgsc.cr.usgs.gov/cwqdr/Piceance/index.shtml
http://wdr.water.usgs.gov/nwisgmap/