Hydrology of Luquillo Biocomplexity: Meeting Summary (Jan 2004)

1. Luquillo Biocomplexity Meeting January 2004 • Hydrology overview • Stream-Hydrology issues • Pike/Scatena research plan

3. Steep Environmental Gradients • Subtropical Dry (1200 mm/yr) to Wet (5000mm/yr) • Windward vs leeward

4. 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

5. Seasonality of Luquillo Climate May Rains

6. Forest Wide Temperature Based on regression of Temp vs elevation, aspect

7. Wet Season Dry Season

8. 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”

9. 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

10. Bisley Hillslope profile Soil and saprolite 10-20 m thick Storage; at 1% water content = 100-200 mm; 1 month throughfall

11. Clay and saprolite subsoil with relatively low ksat = low recharge

12. Storm hydrographs H20 Na, Mg Ca, CL

13. 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

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

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

16. General Hydrologic/land use issues • Municipal water withdrawal • aquatic migrations • Urbanization • Reservoir sedimentation • USGS, landslides • Coastal Plain deforestation • RAMS model

17. Regional-scale changes Synoptic Systems Tradewinds Energy & Moisture Land-Sea Tectonic Uplift Sea Level

19. 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

20. Roads Communication Facilities Water Intakes Roads & Maintenance Buildings

21. Stream/road issuesHydrologic issues • Freeze-thaw • Groundwater discharge • Flooding • overbank, diversion flooding • Erosion of unpaved roads • Damage to bridges and culverts • Landslides

22. Stream/Road-Chemical issues • Applied chemicals (e.g. road salt..) • minor herbicide use • Road material • asphalt, dirt • Emissions • Odum Co2 • Chemical spills • Swimming

23. 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

24. Current Biocomplexity Efforts

25. 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…

29. Slope Raster

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

31. Drainage Area vs Channel Width

32. Slope Mean grain size/Basin area