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 May Rains

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

Annual 7 day Minimum Q90 Q50 Xiphocaris spp. Night Atya spp. Night

Daily Discharge Series No Extraction Extraction = Q95, No Minimum In-stream Flow Extraction = Q95, Minimum In-stream Flow = Q99

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 Land-Sea Tectonic Uplift Sea Level

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

Roads Facilities Water Intakes Roads & Maintenance Buildings Communication Facilities Water Intakes Roads & Maintenance Buildings

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…

Slope Raster

Channel slope vs Drainage area Sonodora = 2.6 km2 Puente Roto = 17.8 km2 Mameyes at RT3 = 34.7 km2

Drainage Area vs Channel Width

Slope Mean grain size/Basin area