Luquillo Biocomplexity Meeting
January 2004
• Hydrology overview
• Stream-Hydrology issues
• Pike/Scatena research plan
Steep Environmental Gradients
–Subtropical Dry (1200 mm/yr) to Wet (5000mm/yr)
– Windward vs leeward
Hydrology Overview
• Steep Environmental Gradients
• Maritime climate with high rainfall frequency
minor seasonality
– 3 rain showers/day, High interception,
– Intense rainfalls; >500 mm/day, 125 mm/day threshold;
Hurricanes, TS, northern fronts
• Dynamic disturbance regime
– Hurricanes, landslides, tree-falls
– Old on inside-young on outside
Seasonality of Luquillo Climate
mm
400
A) Mean monthly rainfall
at 325 masl, 1988-1999
300
200
100
Percent
20
15
B) Percent of annual
peak daily discharge
May
Rains
10
5
20
Percent
15
C) Percent of annual
minimum daily discharge
10
5
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Forest Wide Temperature
Based on regression of Temp vs elevation, aspect
Wet Season
Dry Season
Hydrology Overview
• Steep Environmental Gradients
• Maritime climate with high rainfall
frequency minor seasonality
• Dynamic disturbance regime
– Hurricanes, landslides, tree-falls
– “Old on inside-young on outside”
Hillslope processes
• Deep Clayey soils; 6 + m of saprolite
– Volcanoclastics vs Grandiorite
• Hillslope Catena’s
• Shallow flow paths; < 1 m
– through-flow vs overland flow
– soil compaction, trail erosion
• Landslides; 1000-2000 yr turnover
– roads, elevation, bedrock
– Larsen, Zarin, Walker
Bisley Hillslope profile
Soil and saprolite 10-20 m thick
Storage; at 1% water content = 100-200 mm; 1 month throughfall
Clay and saprolite subsoil with relatively low ksat = low recharge
Storm hydrographs
H20
Na, Mg
Ca, CL
Stream Channel Hydrology
• Headwaters
– Steep gradient, boulders, structural control
– Supply limited
– “clean water”
• Coastal plain
– Alluvial and channelized
– Relatively stable planform morphology
– Aggradation/degradation cycle
Usable area m2 per 1000 m of channel
Annual 7 day
Minimum
1800
Q90
Q50
Xiphocaris spp. Night
1600
1400
1200
Atya spp. Night
1000
800
600
400
200
0
0.0
0.5
1.0
1.5
2.0
2.5
3.0
Discharge, m3/s
3.5
4.0
4.5
Daily Discharge Series
No Extraction
10000
1000
100
<50
Extraction = Q95, No Minimum In-stream Flow
liters/sec
10000
1000
100
<50
Extraction = Q95, Minimum In-stream Flow = Q99
10000
1000
100
<50
10/67 68 69 70 71 72 83 84 85 86 87 88 89 90 91 92 93
General Hydrologic/land use issues
• Municipal water withdrawal
– aquatic migrations
• Urbanization
• Reservoir sedimentation
– USGS, landslides
• Coastal Plain deforestation
– RAMS model
Regional-scale changes
Synoptic
Systems
Tradewinds
Energy &
Moisture
Sea
Level
Land-Sea
Tectonic
Uplift
On-going research efforts
• GIS based-statistical models
– Garcia; low flow prediction, Rivera; peak discharges,
Santos; island wide water chemistry
• Simulation models
– Hall SUNY-ESF; Soil carbon, ET
• Interception and cloud forest hydrology
– Free University of Amsterdam
• Stream water chemistry, N cycling
– W. McDowell, UNH
• Instream flows and water withdrawals
– Pringle UGA
Replacement Costs of Facilities
in the Caribbean National Forest, PR
(Million 1996 $)
Million 1996 $
100
80
Roads
60
40
20
0
Water
Intakes
Buildings
Communication
Facilities
Roads &
Maintenance
Stream/road issues
Hydrologic issues
• Freeze-thaw
• Groundwater discharge
• Flooding
• overbank, diversion flooding
• Erosion of unpaved roads
• Damage to bridges and culverts
• Landslides
Stream/Road-Chemical issues
• Applied chemicals (e.g. road salt..)
– minor herbicide use
• Road material
– asphalt, dirt
• Emissions
– Odum Co2
– Chemical spills
• Swimming
Social considerations
• Social significance of Luquillo Streams
• Seasonality of recreation
– locals vs snowbirds
– don’t go to beach in months with “R”
• Short travel distances and short storms
• Shystostomisis and “dirty” streams
• Swimming skills
Current Biocomplexity Efforts
Channel morphology-aquatic habitat
• GIS-Statistical based approach
– Develop null then evaluate road crossings
• Work Plan
–
–
–
–
–
–
Aug 2003; channel cross-sections
Fall 03; GIS layers
Jan 2004; pebble counts
Spring 04; develop manuscript I
Summer 04; Espirtu Santo, bridges
2005; bridge habitat analysis, water falls…
0
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
5
10
15
20
25
30
Slope Raster
Channel slope vs Drainage area
70
60
Slope (%)
50
40
30
Sonodora = 2.6 km2
20
y = 9.2035x-0.5445
2
R = 0.51
10
0
0
5
10
15
20
25
30
35
40
Drainage Area (km^2)
Puente Roto = 17.8 km2
Mameyes at RT3 = 34.7 km2
Drainage Area vs Channel Width
30
Baseflow/active channel Width (m)
25
20
15
10
5
y = 0.4835x + 4.6603
R2 = 0.5932
0
0
5
10
15
20
Drainage Area (km^2)
25
30
35
40
10000.0
Slope
Slope (ft/mi)
1000.0
100.0
0.4683
y = 26.243x
R2 = 0.7562
10.0
1
10
100
1000
Ratio, Median Grain Size to Drainage Area (mm/sq.mi)
Mean grain size/Basin area
10000