Post on 26-Dec-2015
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]
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 92.32Org-N (mg/L) 1.93 40.94 0.13 40.94 0.20 40.94NH3 (mg/L) 3.68 77.86 0.25 77.86 0.38 77.86NO3+2 (mg/L) 2.00 42.25 0.14 42.25 0.20 42.25* Computed f rom Fort Quitman Gage
Headw ater inputs f rom Upper Rio GrandeOriginal Flow f rom WLE 60% of Median Flow * 40% of Median Flow *
Rio Grande: Alternative Load Scenarios
QUAL-TX Predicted Dissolved Oxygen ConcentrationsSegment 2308: Rio Grande Be low International Dam
4
5
6
7
8
012345678910111213141516171819202122232425262728
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)
Rio Grande: Alternative Load Scenarios
QUAL-TX Predicted Dissolved Oxygen ConcentrationsSegment 2308: Rio Grande Below International Dam
4
5
6
7
8
012345678910111213141516171819202122232425262728
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)
Rio Grande: Alternative Load Scenarios
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]
Simulation Number
Headwater flow (cfs)
Clifton BOD (mg/L)
Clifton NH3-N (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
North Bosque: Alternative Load Scenarios
QUAL-TX Simulations of North Bosque River
4
5
6
7
8
0 20 40 60 80 100
River Kilometers upstream of Lake Waco
DO
Con
cent
rati
on (
mg/
L)
Original 1226_1 1226_4 1226_8
Valley Mills WWTP
Clifton WWTP
Meridian WWTPOriginal = 0.002 cfs; 10 mg/L BOD
1226_1 = 4.9 cfs; 10 mg/L BOD
1226_4 = 4.9 cfs; 20 mg/L BOD
1226_8 = 0.002 cfs; 20 mg/L BOD
Downstream Upstream
QUAL-TX Simulations of North Bosque River
4
5
6
7
8
40 50 60 70
River Kilometers upstream of Lake Waco
DO
Con
cent
rati
on (
mg/
L)
Original 1226_1 1226_4 1226_8
Valley Mills WWTP
Clifton WWTP
Original = 0.002 cfs; 10 mg/L BOD
1226_1 = 4.9 cfs; 10 mg/L BOD
1226_4 = 4.9 cfs; 20 mg/L BOD
1226_8 = 0.002 cfs; 20 mg/L BOD
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 trophic-
level 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
North Bosque Control Periphyton Productivity
0
100
200
300
400
500
Site
Pro
du
ctiv
ity
(μg
Ch
la/m
2 /day
)
0
10
20
30
40
50
Pro
du
ctiv
ity
(mg
DW
/m2/d
ay)
May 2001 Aug 2001 Oct 2001 Jan 2002 Apr 2002
USGS 08095000 North Bosque nr Clifton
0
500
1000
1500
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Month
Mo
nth
ly-M
ea
n D
isc
ha
rge
(c
fs)
2000
2001
2002
North Bosque Ambient Chemistry 2001-2002
0
0.5
1
1.5
2
2.5
BO020 BO040 BO060 BO070 BO090 NC060
Ph
osp
ho
rus
(mg
/L)
0
50
100
150
200
250
Per
iph
yto
n P
rod
uct
ion
(μg
Ch
la /m
2/d
ay)
Average of PO4-P (mg/L) Average of TP (mg/L)
Periphyton Production
Bosque River, TX, P-Limited Production
0.0
0.4
0.8
1.2
0.0 0.4 0.8 1.2 1.6 2.0
Instream SRP (mg/L)
Ind
ex
of
Re
lati
ve
Pro
du
cti
on
(L
ET
SI)
1997-98 2001-2002 Monod Model
Monod Model:umax =0.98; Ks =0.01
R2 = 0.73; p < 0.05
North Bosque Monthly-Mean NPP: 2001-2002
0
1
1
2
2
May June July August
Month
Net
Pri
mar
y P
rod
uct
ion
(m
g O
2/L
/hr)
BO040
BO060
BO070
BO090
USGS 08095000 North Bosque nr Clifton:Monthly-Mean Discharge
0
50
100
150
200
May June July August
Month
Dis
char
ge (c
fs)
2001 Q
2001-2002 Mean Q
2001-2003 Mean Q
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 PeriphytometerTaos Ski Valley, New Mexico
Micro-NDS Periphytometer
Steer Creek, Oregon
Dr. Richard KieslingUS Geological Survey8027 Exchange DriveAustin, TX 78754
kiesling@usgs.gov(512) 927-3505
Contact Information
Dr. Richard KieslingUS Geological Survey8027 Exchange Drive
Austin, TX 78754
kiesling@usgs.gov(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]