Transcript LINKAGES BETWEEN WATER QUALITY AND WATER QUANTITY …

Investigating the Linkage between Water
Quality and Water Quantity in Watershed
Management
Richard L. Kiesling
1United
States Geological Survey, Water Resource Division, Texas District,
8027 Exchange Drive, Austin, TX, 78754
2Environmental
Science Institute, University of Texas, Austin, TX, 78712
Why Evaluate Impact of Streamflow?
•
•
•
•
Streamflow acts as a master variable
Controls Water Residence Time
Regulates Rates of Physical Disturbance
Regulates Nutrient and Carbon Cycling
– nutrient uptake length a function of stream depth and
velocity (e.g., Valett et al. 1996)
– nutrient assimilation and turnover rates a function of
discharge (Butterini and Sabater 1998).
• Regulates Channel Characteristics
– Hydro-geomorphology
Water Resource Functions
• Aesthetics – enhancement of property values
• Habitat – fish and wildlife survival and
reproduction
• Hydro-electric power generation
• Recreation – swimming, boating, fishing
• Seafood production – freshwater inflows for
shellfish and finfish production
• Water quality – assimilation of waste and
production of safe drinking water
• Water supply – Ag, Domestic, Industrial,
Recreation
Investigating the Linkage
• Approach –
– Technical evaluation of the impact of instream
flows on wastewater effluent assimilation
• Methodology –
– Run calibrated QUAL-TX water quality model
with alternative instream flow criteria
– Compare model output for alternative effluent
sets under different static flow conditions
Acknowledgments
•
• TCEQ
Joan Flowers, Carter and Burgess
• TIAER
• US EPA
• Tarleton State University
• Amy Findley
• Jeff Back
Water Quality Simulations: Rio Grande
• Calibrated QUAL-TX Model
• Modified Headwater Flow
– 60% and 40% of median daily flow from Fort Quitman
Gage 1923 through 1950 (3.6 m3/sec and 2.4m3/sec)
• Conserved Pollutant Load
• Modeled Alternative Load Scenarios
– Increased BOD load by 20mg/L for two flow scenarios
• Compared Predicted Instream [DO]
Rio Grande / Rio Bravo Basin
Rio Grande: Alternative Load Scenarios
Headw ater inputs from Upper Rio Grande
Original Flow from WLE
60% of Median Flow *
40% of Median Flow *
Concentration Load (Kg/day) Concentration Load (Kg/day) Concentration Load (Kg/day)
Flow (m3/s)
0.25
3.60
2.40
Temperature (C)
17.80
17.80
17.80
Salinity (ppt)
0.50
0.50
0.50
Conductivity (umhos/cm)
831
830.79
830.79
Chloride (mg/L)
85.27
85.27
85.27
DO (mg/L)
7.05
7.05
7.05
BOD (mg/L)
4.36
92.32
0.30
92.32
0.45
92.32
Org-N (mg/L)
1.93
40.94
0.13
40.94
0.20
40.94
NH3 (mg/L)
3.68
77.86
0.25
77.86
0.38
77.86
NO3+2 (mg/L)
2.00
42.25
0.14
42.25
0.20
42.25
* Computed from Fort Quitman Gage
Rio Grande: Alternative Load Scenarios
QUAL-TX Predicted Dissolved Oxygen Concentrations
Segment 2308: Rio Grande Below International Dam
8
7
6
5
4
28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10
9
8
7
6
5
4
3
2
Original QUAL-TX WLE 7Q2 flow (0.245 m3/s, BOD=20mg/L))
60% of Fort Quitman Median Flow (3.6 m3/s, BOD=20 mg/L)
40% of Fort Quitman Median Flow (2.4 m3/s, BOD=20 mg/L)
1
0
Rio Grande: Alternative Load Scenarios
QUAL-TX Predicted Dissolved Oxygen Concentrations
Segment 2308: Rio Grande Below International Dam
8
7
6
5
4
28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9
8
7
6
5
4
3
2
60% of Fort Quitman Median Flow (3.6 m3/s, BOD=20 mg/L)
40% of Fort Quitman Median Flow (2.4 m3/s, BOD=20 mg/L)
Additional BOD Load Scenario 1 (Flow=3.6 m3/s, BOD=40)
Additional BOD Load Scenario 2 (Flow=2.4 m3/s, BOD=40)
1
0
Water Quality Simulations: North Bosque
• Used Calibrated TNRCC QUAL-TX Model
• Modified Headwater Flow
– Default Instream Flow restriction based on 60% or 40%
of median daily flow recorded at Clifton Gage
• Conserved Pollutant Load
• Modeled Alternative Load Scenarios
– Increased BOD load by 20mg/L for two flow scenarios
• Compared Predicted Instream [DO]
BO040
BO060
BO070
BO090
NC060
TIAER Graphic; used by permission
North Bosque: Alternative Load Scenarios
Simulation
Number
Headwater
flow (cfs)
Clifton BOD
(mg/L)
Clifton NH3N (mg/L)
Valley Mills
BOD (mg/L)
Valley Mills
NH3-N (mg/L)
TCEQ/
TNRCC
0.002
10
12
10
12
1
4.9
10
12
10
12
2
1.0
10
12
10
12
3
0.6
10
12
10
12
4
4.9
20
15
10
12
5
4.9
10
12
20
15
6
0.6
20
15
10
12
7
0.6
10
12
20
15
8
0.002
20
15
10
12
9
0.002
10
12
20
15
QUAL-TX Simulations of North Bosque River
8
DO Concentration (mg/L)
Downstream
Upstream
7
Valley Mills WWTP
6
Meridian WWTP
Original = 0.002 cfs; 10 mg/L BOD
1226_1 = 4.9 cfs; 10 mg/L BOD
5
1226_4 = 4.9 cfs; 20 mg/L BOD
1226_8 = 0.002 cfs; 20 mg/L BOD
Clifton WWTP
4
0
20
40
60
80
River Kilometers upstream of Lake Waco
Original
1226_1
1226_4
1226_8
100
QUAL-TX Simulations of North Bosque River
8
DO Concentration (mg/L)
Valley Mills WWTP
7
6
Original = 0.002 cfs; 10 mg/L BOD
1226_1 = 4.9 cfs; 10 mg/L BOD
5
1226_4 = 4.9 cfs; 20 mg/L BOD
Clifton WWTP
1226_8 = 0.002 cfs; 20 mg/L BOD
4
40
50
60
70
River Kilometers upstream of Lake Waco
Original
1226_1
1226_4
1226_8
Simulation Study Conclusions
• Maintenance of instream flows above critical low
flows increased modeled assimilative capacity
• Potential exists for economic trade-off between
wastewater treatment costs and instream flow to
maintain assimilative capacity
• Integrated water resource management requires
the simultaneous assessment of streamflow
manipulation and assimilative capacity
– Does this apply to all constiuents?
System Model of Nutrients and
Watershed Eutrophication
• Nutrient supply can limit algal production
• Nutrient enrichment from watershed and marine
sources can control extent of limitation
• Control Points within watersheds dictate trophiclevel responses to nutrient enrichment; for
example
– Frequency and magnitude of loads
– Spatial and temporal change in LULC
– Hydro modification (entrenchment, diking)
In-stream Methods: algal production
• NDS periphytometers apparatus design –
– Liquid media diffusing through two-layer substrate
• 0.45 micron nylon barrier filter
• GFF substrate - analyzed for algal biomass or carbon
• Factorial Experiments – factors, 1 level each,
interaction term
–
–
–
–
Six Sites in North Bosque River Watershed
Nutrient media additions of 350 uM N and 100 uM P
Eight replicates per treatments
10-14 day deployments; micro and macro methods
BO040
BO060
BO070
BO090
NC060
TIAER Graphic; used by permission
Matlock Periphytometer, North Bosque River, Hico TX
Micro-NDS Periphytometer,
North Bosque River, Hico TX
May 2001
Aug 2001
Oct 2001
Site
Jan 2002
Apr 2002
400
40
300
30
200
20
100
10
0
0
Productivity (mg DW/m2 /day)
500
bo
04
0
bo
06
0
bo
07
0
bo
09
0
nc
06
0
bo
04
0
bo
06
0
bo
07
0
bo
09
0
nc
06
0
bo
04
0
bo
06
0
bo
07
0
bo
09
0
nc
06
0
bo
04
0
bo
06
0
bo
07
0
bo
09
0
nc
06
0
bo
04
0
bo
06
0
bo
07
0
bo
09
0
nc
06
0
bo
02
0
Productivity (μg Chla/m 2/day)
North Bosque Control Periphyton Productivity
50
USGS 08095000 North Bosque nr Clifton
Monthly-Mean Discharge (cfs)
1500
2000
2001
2002
1000
500
0
Jan
Feb
Mar
Apr
May
Jun
Jul
Month
Aug
Sep
Oct
Nov
Dec
2
200
1.5
150
1
100
0.5
50
0
0
BO020
BO040
BO060
Average of PO4-P (mg/L)
Periphyton Production
BO070
BO090
NC060
Average of TP (mg/L)
2
250
(μg Chla /m /day)
2.5
Periphyton Production
Phosphorus (mg/L)
North Bosque Ambient Chemistry 2001-2002
Index of Relative Production
(LETSI)
Bosque River, TX, P-Limited Production
1.2
0.8
Monod Model:
umax =0.98; Ks =0.01
0.4
2
R = 0.73; p < 0.05
0.0
0.0
0.4
0.8
1.2
1.6
Instream SRP (mg/L)
1997-98
2001-2002
Monod Model
2.0
North Bosque Monthly-Mean NPP: 2001-2002
Net Primary Production (mg O
2 /L/hr)
2
2
BO040
BO060
1
BO070
BO090
1
0
May
June
July
Month
August
USGS 08095000 North Bosque nr Clifton:
Monthly-Mean Discharge
200
2001 Q
2001-2002 Mean Q
2001-2003 Mean Q
Discharge (cfs)
150
100
50
0
May
June
July
Month
August
Conclusions: Watershed Eutrophication
• Nutrient-limited periphyton primary production
conforms to resource-consumer model of
population growth based on resource supply rate
• Periphyton primary productivity is elevated along
the instream nutrient concentration gradient,
documenting a change in trophic status
• Periphyton and water-column primary
productivity at Clifton (BO090) track mean
discharge as well as nutrient concentration
Micro-NDS Periphytometer
Taos Ski Valley, New Mexico
Dr. Richard Kiesling
US Geological Survey
8027 Exchange Drive
Austin, TX 78754
[email protected]
(512) 927-3505
Micro-NDS Periphytometer
Steer Creek, Oregon
Contact Information
Dr. Richard Kiesling
US Geological Survey
8027 Exchange Drive
Austin, TX 78754
[email protected]
(512) 927-3505
Buffalo Bayou Example
• Proposed to augment flow of Buffalo Bayou
from upstream flood control reservoir
• Maximum annual demand for instream flow
releases was 62,985 ac-ft per year
• WWTP alternative cost $22.1 million for
construction and operation (2001 dollars)
• Alternatives approximately equivalent at
raw water cost of $350 per ac-ft (2001 dollars)
Economic Evaluation Observations
• Example illustrates the potential for benefits
analysis associated with the maintenance of
instream flows
• Example demonstrates the potential value of
integrated functional analysis of water
quality and water quantity
• Raises questions regarding costs estimates
available for this type of planning exercise
Water Quality Simulations: Rio Grande
• Calibrated QUAL-TX Model
• Modified Headwater Flow
– 60% and 40% of median daily flow from Fort Quitman
Gage 1923 through 1950 (3.6 m3/sec and 2.4m3/sec)
• Conserved Pollutant Load
• Modeled Alternative Load Scenarios
– Increased BOD load by 20mg/L for two flow scenarios
• Compared Predicted Instream [DO]