GIS Mapping

GIS Mapping Base maps provide reference for additional data layers Base maps of either Orthophotos Topographic maps Combination

Topographic map as base map Overlays identify subwatershed boundaries and streams

Cottonwood Orthophoto base map with subwatershed boundaries

Southwest Creeks Orthophoto base map with watershed & stream overlays

Layers Layers exist for: Streams Roads Subwatersheds Soils Others easily added Land Use ?

Conesus Lake All soils may be differentiated Topo Map with overlays Subwatersheds Streams Soils

SandPoint Soils grouped by dominant soil series Orthophoto base map with soils overlay

Future Needs Pretty Maps vs. GIS Maps with various parameters are easily generated Is this the best use of GIS capabilities Use GIS to develop interface with database Spatial interface for spatial data

Example Screenshot Database ArcMap GUI

P Speciation in Sediments

P Speciation Distribution of P among various sediment physicochemical phases. P associated with sediment solids and pore water Determined by selective removal of each phase in a sequential extraction procedure

Sequential Extractions Removal of elements associated with discrete phases Optimized for a specific element of group of elements Optimization based on chemical reactivity and associations in the sediment Extractions become “operationally defined” fractions

P Chemistry in Sediments Exists primarily as phosphate in inorganic fractions H2PO4- or HPO4-2 Forms strong bonds through ligand exchange with oxyhdroxides of Fe, Al and Mn Organic fractions are more complex and variable

P Interactions with Fe oxyhydroxide Fe-OH Easily exchangeable outer sphere complex (hours) + H2PO4- Fe-OH Specifically adsorbed inner sphere complex (days) Fe-OH + OH- Fe-H2PO4 Anion penetration by ligand exchange (weeks) Fe-O O P + H2O Fe-O OH

Potential P Fractions Labile Pore water and easily exchangeable P In equilibrium with solid phases Most reactive, mobile and bioavailable fraction

Potential P Fractions Ca associated P Associated with CaCO3 phases Produces discrete Ca phosphate phases over time Ca phosphate phases may be directly precipitated Relatively insoluble, low bioavailability

Potential P Fractions Fe & Mn oxyhydroxide associated P Specifically adsorbed onto oxyhydroxide surfaces, possibly occluded May form discrete Fe(II) phosphate phases Relatively insoluble, but subject to changes in redox conditions Low bioavailability in solid phase

Potential P Fractions Al oxyhydroxide associated P Similar in reactivity to Fe Not subject to redox remobilization Prompts use of alum to remediate high P lakes Low bioavailability in solid phase

Potential P Fractions Organic P Complex and variable phases Dynamic fraction but poorly understood Fractionation of organic P is possible

Sequential Extraction Scheme Acetic Acid - removes free carbonates NH4F - removes Al-P NaOH - removes organic P HA/HNO3 - reducible amorphous OxHy HA/HCl - reducible crystalline OxHy HCl - Ca-P

Sequential Extraction Results

Sequential Extraction Results

Future Work Fractionation of Conesus Lake sediments Fractionation of agricultural soil samples