Download - Stream Asset Inventory GIS Model

Johnson County AIMShttp://aims.jocogov.org

Stream Asset Inventory GIS Model

• Goals – – Use a variety of spatial

datasets to test feasibility and accuracy of modeling stream types and orders

– Support the field data collection efforts by providing accurate reference data prior to sampling


Pilot Study

• Test watershed is Blue River in southeast corner of Johnson County

• Approx. 100 mile2


Process

• Use spatial analysis and hydrological modeling tools to model stream network and environmental conditions

• Solid DEM is basis of accurate results

• Majority of hydrologic products derived from DEM including the streams, subwatersheds, slope, etc


Tools

• Free extensions packaged with Arc8 and AV3.x– Hydrology Modelling, HydroAnalyst

• Free 3rd party extensions for use with ESRI products– ArcHydro, Strahler Stream Order…


DEM Source


Filled DEM


Flow Direction


Flow Accumulation


Watershed Delineation


Stream Delineation


Slope


Stream Order


Additional Attributes

• Slope – Average

• Sinousity – Curve/Line

• Slope/Sinousity – Gives Condition Index

• Channel Stability (Erodiblility) – Slope/Soil


Modeled Hydrology


Challenges of Watershed Delineation

• Not an exact science and there’s no standard

• Typically done with 30 meter DEM

• We’re not hydrologists

• Testing the various inputs to generating watershed data

• Contour vs. Masspoint• Burning In Streams• Establishing Input Parameter Thresholds• Handling high resolution data • Handling Anomalies


High Resolution Data


Anomalies


Next Steps

Subwatersheds &Streams

Env. ConditionsImpervious surfaceSoilVeg Coveretc…

Develop classification of streams and subwatersheds

Sensitive ImpactedNon-supporting Restorable


Layers for Analysis

• Essential– Impervious Surfaces – Current Land Use– Future Land Use

• Helpful– Vegetative Cover– Road Crossings– Sewer Lines– Developable Land– Wetlands– Soils– Pollution Sources


Contours

DEM FlowDirection

FlowAccumulation

Masspoints

SlopeStreams Subwatersheds

StreamOrder

FilledDEM

Sinousity

StreamOrder

Obstructions

Veg Cover

Bridges

Landuse

Soils

etc…


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Data Collection

• Custom forms on pocket pc

• GPS wired to pocket pc for data capture

• Sync nightly through internet back to master database

Download - Stream Asset Inventory GIS Model

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