Transcript November 3rd presentation

Hydrologic Model of the
Mayagüez Bay Watersheds:
Progress Report
Eric Harmsen, Associate Professor
Dept. of Agricultural and Biosystems Engineering
Marcel Giovanni Prieto, Graduate Student
Dept. of Civil Engineering and Surveying
Acknowledgements
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NASA-EPSCoR
US Geologic Survey
Sea Grant
U.S. Army Corps of Engineers (ERDC)
LARSIP Laboratory
Puerto Rico Water Resources and
Environmental Research Institute
Professor Nazario Ramirez, UPRM
Students: Sandra Ortiz, Richard Diaz,
Moises Angeles Malaspina, Christian
Calderon
Some Water Issues in Puerto Rico
 Water conflicts between agricultural and non-agricultural
community (Lajas, PR)
 Sediment transport is contaminating marine resources at
numerous coastal areas in PR
 Saltwater intrusion is threatening groundwater resources in
the north and south coast of PR
 Dropping groundwater elevations occurring in the South
Coast.
 Many of the principal reservoirs have become partially filled
with sediment since their construction, reducing their
effectiveness in providing water supplies and mitigating flood
peaks. (e.g., Carraízo Reservoir which supplies San Juan)
 Problems with the water supply service of 700,000 families
at the present time in the island (Nuevo Día 05 Feb. 2005)
Sediment Discharge to the
Mayagüez Bay
Rio Grande de Anasco Outlet
Water related issues will become
even more serious in the future
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Potential climate change
Urban growth
Increasing population
Increasing cost of water and energy
Contamination of water supplies
Environmental impacts from
changing flows
Objective
• To develop an integrated hydrologic model for the
Mayaguez Bay Watersheds for the purpose of
• Estimating the components of the hydrologic cycle
• Evaluate the water balance under climate change
conditions (uncoupled)
Longer-term objectives:
• Apply an integrated hydrologic model coupled with a
regional atmospheric model (e.g., RAMS/TOPMODEL)
• Evaluate the water balance for the entire island
Integrated Hydrologic Modeling
MOTIVATION
We will be able to address scientific and
practical questions related to the
hydro/atmospheric system
 How might changes in global/local weather affect
our water supply
 How will urban growth effect the hydrology (land
use change, Urban Head Island effect)
 Evaluate the effect of specific types of storms on
 Flooding
 Landslide potential
Modeling Strategy
1.
Multi-watershed model (short-term)
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2.
Develop and calibrate hydrologic model
Use output from climate change simulations
from an atmospheric simulation model as
input to the hydrologic model
Island-wide model (long-term)
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Develop and calibrate hydrologic model
Hydrologic model coupled with RAMS
Qualification
Model will be developed based on a rough
calibration
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Available groundwater elevations
USGS gauging station – Total daily volume
(not hydrographs)
Overland flow only (no channel flow)
Model Selection
Requirements
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Should simulate
• Overland flow
• Vadose zone flow
• Groundwater flow (preferably in 3-D)
• 1-D channel flow
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Should run on a supercomputer
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Source code should be freely available
Models we evaluated:
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Mike She, WASH123D, IHM, GHSSA
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Conceptual model development
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Identification of data sources
Delineation of study area
Conceptualize surface, soil and subsurface
systems
Development of GIS map
Perform simplified GIS water balance
Study Area
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Requirements
• Two or more watersheds
• Boundary along coast
• Large topographic relief
• Include alluvial and bedrock aquifers
• Various land use categories
GIS Water Balance of the
Mayaguez Drainage Basin
Precip = ET + RO + Rch +ΔS
Precip = Precipitation
ET = Evapotranspiration
RO = Surface Runoff
Rch = Aquifer Recharge
ΔS = Change in soil moisture storage
Soil Moisture Content
Percent Soil Moisture
UPR-Mayaguez Campus - September 2005
50
40
30
Sensor 1
20
Sensor 2
10
0
0
5
10
15
20
Days
25
30
35
Soil Moisture Content
UPR - Mayaguez Campus January 2005
Percent Moisture
Content
25
20
15
Sensor 1
10
Sensor 2
5
0
5
10
15
20
Days
25
30
Potential Evapotranspiration
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Hargreaves-Samani Method
PET = 0.0023 x Ra x (T +17.8) x
(Tmax – Tmin)0.5
PET = potential or reference ET
Ra = extraterrestrial evapotranspiration
T = average daily air temperature
Tmin = average daily minimum temperature
Tmax = average daily maximum temperature
Hydrologic Model - Evapotranspiration
ET o Hargreaves-Samani (mm/day)
Evaluation of Simplified
Method
Surface Elevation
7
6
5
4
3
2
2
3
4
5
6
7
ET o Penman-Monteith (mm/day)
Air Temperature
Reference Evapotranspiration
Hydrologic Model - Evapotranspiration
Kc Literature
Actual ET
September
Reference ET X
NDVI
Actual ET January
Hydrologic Model – Surface Runoff
LAND COVER
MONTHLY RUNOFF
COEFFICIENT
MONTHLY RAINFALL
MONTHLY RUNOFF
Aquifer Recharge
September
59.7 mm Average
January
Aquifer
Recharge
was zero
at all
locations
Depth of Water
(mm)
Mayaguez Bay Drainage Area Water Balance
300
250
200
150
100
50
0
September
January
Rain
Runoff
Recharge
Water Balance Component
ET
Percent of Rainfall
Mayaguez Bay Drainage Area Water Balance
80%
60%
40%
September
January
20%
0%
Runoff
Recharge
Water Balance Component
ET
Global Warming
http://www.gfdl.noaa.gov/~tk/climate_dynamics/fig1.gif
PET = 0.0023 x Ra x (T +17.8) x (Tmax – Tmin)0.5
“ There has also been a general trend
toward reduced diurnal temperature
range, mostly because nights have
warmed more than days.”
- Union of Concerned Scientists
http://www.ucsusa.org/global_warming/science/early-warning-signs-ofglobal-warming-heat-waves.html
Global Climate Circulation Model – Caribbean Area
DOE - Accelerated Climate Prediction Initiative
Air Temperature
Annual Rainfall
27.2
1050
27
1000
26.8
Air Temperature (C)
Rainfall (mm/year)
1100
950
900
850
800
750
26.6
26.4
26.2
26
25.8
700
25.6
650
25.4
600
1980
2000
2020
2040
2060
2080
2100
25.2
1980
2120
2000
2020
2040
Year
2080
2100
2120
2080
2100
2120
Net Radiation
Relative Humidity
76
628
75
626
624
74
622
Rnet (W/m2)
73
RH (%)
2060
Year
72
71
620
618
616
70
614
69
612
68
610
67
1980
608
1980
2000
2020
2040
2060
Year
2080
2100
2120
2000
2020
2040
2060
Year
Some Climate Change Results
Increase in ET relative to Year 2000
2050
2100
mm/month
2.7
5.4
Million Gallons
per month
584
1168
Drop
in Aquifer
Drop
in the Recharge relative to
Year 2000
Groundwater
Drop in the
Groundwater
Elevation relative to
Year 2000
mm
2050
12.2
2100
24.2
Reduction in Aquifer Recharge During the
Million Gallons
Month of September
per
80 month
525
75
1045
Recharge (mm/month)
Elevation relative to
Year 2000
mm/month
mm
2050
2.4
2050
13.5
2100
4.8
2100
27.0
70
65
60
55
50
45
40
1980
2000
2020
2040
2060
Year
2080
2100
2120
Conclusions from GIS Water
Balance Analysis
During the next 50 to 100 years:
 ET can be expected to increase by 3 to 5
mm/month
 In the worse case the aquifer recharge will
also drop by this amount
 The expected drop in the water table is
between 13 to 27 mm.
 Increase urban development may
decrease aquifer recharge and increase
surface runoff.
Numerical Model
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MIKE SHE
• Advantages
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Easy to use
3-D groundwater
Water balance analysis
tools are excellent
Can simulate other
processes: sediment and
solute transport
• Disadvantages
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Only runs on a PC
Documentation is not
complete
OLF – Diffuse wave
approximation of the Saint
Venant equations
UZ – Richards Equation, gravity
method, 2 layer water balance
SZ – standard groundwater
equation (MODFLOW)
Simulation of average conditions
for Mayaguez Bay Area
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Rainfall – Time series for Hacienda Constanza
weather station
Manning’s n: 0.07
Soil: Loamy Clay
Potential ET: 4.4 mm/day
Aquifer
• type: unconfined
• thickness: 33 m
• conductivity: 0.33 m/day
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Initial groundwater elevation: 0 m below
surface
Depth of Water
(mm)
September Mayaguez Bay Drainage Area Water Balance
Comparison of GIS and MIKE SHE Water Balance
450
400
350
300
250
200
150
100
50
0
GIS
MIKE SHE
Rain
Runoff
Recharge
ET
Water Balance Component
Delt S
Future Work
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Model Calibration
• Groundwater elevations
• Daily Surface water Volumes
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Climate Change scenarios
• Decide which climate parameters to
vary
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Write Proposals for more funding
(NASA-NEWS)