Hydrologic Model of the Hydrologic Model of the MayagMayagüeüez Bay Watersheds: z Bay Watersheds:

Progress ReportProgress Report

Eric Harmsen, Associate ProfessorEric Harmsen, Associate ProfessorDept. of Agricultural and Biosystems EngineeringDept. of Agricultural and Biosystems Engineering

Marcel Giovanni Prieto, Graduate StudentMarcel Giovanni Prieto, Graduate StudentDept. of Civil Engineering and Surveying Dept. of Civil Engineering and Surveying

AcknowledgementsAcknowledgements NASA-EPSCoRNASA-EPSCoR US Geologic SurveyUS Geologic Survey Sea GrantSea Grant U.S. Army Corps of Engineers (ERDC)U.S. Army Corps of Engineers (ERDC) LARSIP LaboratoryLARSIP Laboratory Puerto Rico Water Resources and Puerto Rico Water Resources and

Environmental Research InstituteEnvironmental Research Institute Professor Nazario Ramirez, UPRMProfessor Nazario Ramirez, UPRM Students: Sandra Ortiz, Richard Diaz, Students: Sandra Ortiz, Richard Diaz,

Moises Angeles Malaspina, Christian Moises Angeles Malaspina, Christian CalderonCalderon

Some Water Issues in Puerto RicoSome Water Issues in Puerto Rico

Water conflicts between agricultural and non-agricultural Water conflicts between agricultural and non-agricultural community (Lajas, PR)community (Lajas, PR)

Sediment transport is contaminating marine resources Sediment transport is contaminating marine resources at numerous coastal areas in PRat numerous coastal areas in PR

Saltwater intrusion is threatening groundwater Saltwater intrusion is threatening groundwater resources in the north and south coast of PRresources in the north and south coast of PR

Dropping groundwater elevations occurring in the South Dropping groundwater elevations occurring in the South Coast.Coast.

Many of the principal reservoirs have become partially filled Many of the principal reservoirs have become partially filled with sediment since their construction, reducing their with sediment since their construction, reducing their effectiveness in providing water supplies and mitigating flood effectiveness in providing water supplies and mitigating flood peaks.peaks. (e.g., Carra(e.g., Carraízo Reservoir which supplies San Juan)ízo Reservoir which supplies San Juan)

Problems with the water supply service of 700,000 Problems with the water supply service of 700,000 families at the present time in the island (families at the present time in the island (Nuevo Nuevo DíaDía 05 Feb. 05 Feb. 2005)2005)

Sediment Discharge to the Sediment Discharge to the MayagMayagüüez Bayez Bay

Rio Grande de Anasco Outlet

Water related issues will become Water related issues will become even more serious in the future even more serious in the future

Potential climate changePotential climate change Urban growthUrban growth Increasing populationIncreasing population Increasing cost of water and energyIncreasing cost of water and energy Contamination of water suppliesContamination of water supplies Environmental impacts from Environmental impacts from

changing flowschanging flows

ObjectiveObjective

• To develop an integrated hydrologic model for the To develop an integrated hydrologic model for the Mayaguez Bay Watersheds for the purpose of Mayaguez Bay Watersheds for the purpose of

• Estimating the components of the hydrologic cycleEstimating the components of the hydrologic cycle

• Evaluate the water balance under climate change Evaluate the water balance under climate change conditions (uncoupled)conditions (uncoupled)

Longer-term objectives:Longer-term objectives:

• Apply an integrated hydrologic model coupled with a Apply an integrated hydrologic model coupled with a regional atmospheric model (e.g., RAMS/TOPMODEL)regional atmospheric model (e.g., RAMS/TOPMODEL)

• Evaluate the water balance for the entire islandEvaluate the water balance for the entire island

Integrated Hydrologic ModelingIntegrated Hydrologic Modeling

MOTIVATIONMOTIVATION We will be able to address scientific and We will be able to address scientific and

practical questions related to the practical questions related to the hydro/atmospheric systemhydro/atmospheric system

How might changes in global/local weather affect How might changes in global/local weather affect our water supplyour water supply

How will urban growth effect the hydrology (land How will urban growth effect the hydrology (land use change, Urban Head Island effect)use change, Urban Head Island effect)

Evaluate the effect of specific types of storms on Evaluate the effect of specific types of storms on

FloodingFlooding

Landslide potentialLandslide potential

Modeling StrategyModeling Strategy

1.1. Multi-watershed model (short-term)Multi-watershed model (short-term)• Develop and calibrate hydrologic modelDevelop and calibrate hydrologic model• Use output from climate change simulations Use output from climate change simulations

from an atmospheric simulation model as from an atmospheric simulation model as input to the hydrologic modelinput to the hydrologic model

2.2. Island-wide model (long-term)Island-wide model (long-term)• Develop and calibrate hydrologic modelDevelop and calibrate hydrologic model• Hydrologic model coupled with RAMSHydrologic model coupled with RAMS

QualificationQualification

Model will be developed based on a Model will be developed based on a roughrough calibrationcalibration

• Available groundwater elevationsAvailable groundwater elevations• USGS gauging station – Total daily volume USGS gauging station – Total daily volume

(not hydrographs)(not hydrographs)• Overland flow only (no channel flow)Overland flow only (no channel flow)

Model SelectionModel Selection

RequirementsRequirements Should simulate Should simulate

• Overland flowOverland flow• Vadose zone flowVadose zone flow• Groundwater flow (preferably in 3-D)Groundwater flow (preferably in 3-D)• 1-D channel flow1-D channel flow

Should run on a supercomputerShould run on a supercomputer Source code should be freely available Source code should be freely available

Models we evaluated:Models we evaluated: Mike SheMike She, WASH123D, IHM, GHSSA, WASH123D, IHM, GHSSA

• Conceptual model developmentConceptual model development Identification of data sourcesIdentification of data sources Delineation of study areaDelineation of study area Conceptualize surface, soil and subsurface Conceptualize surface, soil and subsurface

systemssystems Development of GIS mapDevelopment of GIS map Perform simplified GIS water balancePerform simplified GIS water balance

Study AreaStudy Area

Requirements Requirements • Two or more watershedsTwo or more watersheds• Boundary along coastBoundary along coast• Large topographic reliefLarge topographic relief• Include alluvial and bedrock aquifersInclude alluvial and bedrock aquifers• Various land use categoriesVarious land use categories

GIS Water Balance of the GIS Water Balance of the Mayaguez Drainage BasinMayaguez Drainage Basin

Precip = ET + RO + Rch +ΔS

Precip = PrecipitationET = EvapotranspirationRO = Surface RunoffRch = Aquifer RechargeΔS = Change in soil moisture storage

Soil Moisture ContentSoil Moisture Content

UPR-Mayaguez Campus - September 2005

0

10

20

30

40

50

0 5 10 15 20 25 30 35

Days

Per

cen

t S

oil

Mo

istu

re

Sensor 1

Sensor 2

Soil Moisture ContentSoil Moisture ContentUPR - Mayaguez Campus January 2005

0

5

10

15

20

25

5 10 15 20 25 30

Days

Per

cen

t M

ois

ture

C

on

ten

t

Sensor 1

Sensor 2

Potential EvapotranspirationPotential Evapotranspiration Hargreaves-Samani MethodHargreaves-Samani Method

PET = 0.0023 x RPET = 0.0023 x Raa x (T +17.8) x x (T +17.8) x (T(Tmaxmax – T – Tminmin))0.50.5

PET = potential or reference ETPET = potential or reference ETRRaa = extraterrestrial evapotranspiration = extraterrestrial evapotranspirationT = average daily air temperatureT = average daily air temperatureTTminmin = average daily minimum temperature = average daily minimum temperatureTTmaxmax = average daily maximum temperature = average daily maximum temperature

Hydrologic Model - EvapotranspirationHydrologic Model - Evapotranspiration

2

3

4

5

6

7

2 3 4 5 6 7

ETo Penman-Monteith (mm/day)

ET

o H

arg

reav

es-S

aman

i (m

m/d

ay)

Surface ElevationEvaluation of Simplified Method

Air Temperature Reference Evapotranspiration

Hydrologic Model - EvapotranspirationHydrologic Model - Evapotranspiration

Kc Literature

Reference ET X

Actual ET September

NDVI

Actual ET January

Hydrologic Model – Surface RunoffHydrologic Model – Surface RunoffMONTHLY RUNOFF

COEFFICIENT

MONTHLY RAINFALL

LAND COVER

MONTHLY RUNOFF

Aquifer RechargeAquifer Recharge

January

Aquifer Rechargewas zeroat all locations

September

59.7 mm Average

Mayaguez Bay Drainage Area Water Balance

050

100150200250300

Rain Runoff Recharge ET

Water Balance Component

De

pth

of

Wa

ter

(m

m)

September

January

Mayaguez Bay Drainage Area Water Balance

0%

20%

40%

60%

80%

Runoff Recharge ET

Water Balance Component

Per

cen

t o

f R

ain

fall

September

January

Global WarmingGlobal Warming

http://www.gfdl.noaa.gov/~tk/climate_dynamics/fig1.gif

PET = 0.0023 x RPET = 0.0023 x Raa x (T +17.8) x x (T +17.8) x (T(Tmaxmax – T – Tminmin))0.50.5

“ “ There has also been a general trend There has also been a general trend toward reduced diurnal temperature toward reduced diurnal temperature range, mostly because nights have range, mostly because nights have warmed more than days.”warmed more than days.”

- Union of Concerned Scientists- Union of Concerned Scientistshttp://www.ucsusa.org/global_warming/science/early-warning-signs-of-global-http://www.ucsusa.org/global_warming/science/early-warning-signs-of-global-

warming-heat-waves.htmlwarming-heat-waves.html

Annual Rainfall

600

650

700

750

800

850

900

950

1000

1050

1100

1980 2000 2020 2040 2060 2080 2100 2120

Year

Rai

nfa

ll (

mm

/yea

r)

Air Temperature

25.2

25.4

25.6

25.8

26

26.2

26.4

26.6

26.8

27

27.2

1980 2000 2020 2040 2060 2080 2100 2120

Year

Air

Tem

per

atu

re (

C)

Relative Humidity

67

68

69

70

71

72

73

74

75

76

1980 2000 2020 2040 2060 2080 2100 2120

Year

RH

(%

)

Net Radiation

608

610

612

614

616

618

620

622

624

626

628

1980 2000 2020 2040 2060 2080 2100 2120

Year

Rn

et (

W/m

2)

Global Climate Circulation Model – Caribbean AreaDOE - Accelerated Climate Prediction Initiative

Some Climate Change ResultsSome Climate Change Results

mm/monthMillion Gallons

per month2050 2.7 5842100 5.4 1168

Increase in ET relative to Year 2000

Drop in the Groundwater

Elevation relative to Year 2000

mm2050 13.52100 27.0

Reduction in Aquifer Recharge During the Month of September

40

45

50

55

60

65

70

75

80

1980 2000 2020 2040 2060 2080 2100 2120

Year

Rec

har

ge

(mm

/mo

nth

)

Conclusions from GIS Water Conclusions from GIS Water Balance AnalysisBalance Analysis

During the next 50 to 100 years:During the next 50 to 100 years: ET can be expected to increase by 3 to 5 ET can be expected to increase by 3 to 5

mm/month mm/month In the worse case the aquifer recharge will In the worse case the aquifer recharge will

also drop by this amountalso drop by this amount The expected drop in the water table is The expected drop in the water table is

between 13 to 27 mm.between 13 to 27 mm. Increase urban development may Increase urban development may

decrease aquifer recharge and increase decrease aquifer recharge and increase surface runoff.surface runoff.

Numerical ModelNumerical Model MIKE SHEMIKE SHE

• AdvantagesAdvantages Easy to useEasy to use 3-D groundwater3-D groundwater Water balance analysis Water balance analysis

tools are excellenttools are excellent Can simulate other Can simulate other

processes: sediment and processes: sediment and solute transportsolute transport

• DisadvantagesDisadvantages Only runs on a PCOnly runs on a PC Documentation is not Documentation is not

completecomplete

OLF – Diffuse wave approximation of the Saint Venant equationsUZ – Richards Equation, gravity method, 2 layer water balanceSZ – standard groundwater equation (MODFLOW)

Simulation of average conditions Simulation of average conditions for Mayaguez Bay Areafor Mayaguez Bay Area

Rainfall – Time series for Hacienda Constanza Rainfall – Time series for Hacienda Constanza weather stationweather station

Manning’s n: 0.07Manning’s n: 0.07 Soil: Loamy ClaySoil: Loamy Clay Potential ET: 4.4 mm/dayPotential ET: 4.4 mm/day Aquifer Aquifer

• type: unconfinedtype: unconfined• thickness: 33 mthickness: 33 m• conductivity: 0.33 m/dayconductivity: 0.33 m/day

Initial groundwater elevation: 0 m below Initial groundwater elevation: 0 m below surfacesurface

September Mayaguez Bay Drainage Area Water BalanceComparison of GIS and MIKE SHE Water Balance

050

100150200250300350400450

Rain Runoff Recharge ET Delt S

Water Balance Component

Dep

th o

f W

ater

(m

m)

GIS

MIKE SHE

Future WorkFuture Work

Model CalibrationModel Calibration• Groundwater elevationsGroundwater elevations• Daily Surface water VolumesDaily Surface water Volumes

Climate Change scenariosClimate Change scenarios• Decide which climate parameters to Decide which climate parameters to

varyvary Write Proposals for more funding Write Proposals for more funding

(NASA-NEWS)(NASA-NEWS)