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Modeling, and Soil Survey

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Presentation on theme: "Modeling, and Soil Survey"— Presentation transcript:

1 Modeling, and Soil Survey
Sinkholes Modeling, and Soil Survey

2 Objectives Examine a few techniques and efforts to model karst features for map unit and/or component delineation. Consider some case studies of mapping and updating karst areas: Lawrence co, Indiana Springfield plateau, Missouri

3 GIS techniques to enhance identification of karst
Karst: Dade county, MO

4 Same area: 10m DEM, hillshade relief, hypso lines
Source: F. Young, NRCS

5 Sinkholes: 3x vertical exaggeration, 5m display resolution (10m DEM)
Source: F. Young, NRCS

6 Flowaccumulation (multi-path): karst area
Source: F. Young, NRCS Didn’t work that well…

7 Karst: wetness index (multi-path)
Bluer = higher wetness index. Works fairly well for some sinkholes. However, not all upland wet areas are sinkholes.

8 Can we model these sinkholes?
Moderately high elevation Avg about 325m; range about 315 to 335m High Flow accumulation Above about 200 High Wetness Index Above about 9 Not on the stream network Not so easy to model Source: F. Young, NRCS

9 Fuzzy Membership Model for Sinks
Higher-elevation valleys confounded w sinks Modeled using SIE: Full membership = 100. What about using streams in the model? USGS streams layer is incomplete (missing tributaries) Modeled stream network runs into sinks

10 Fuzzy Membership Model w more restrictive lower elevation criteria
(lost the lowest elevation sinkhole)

11 Karst plain: Pierpont area, Boone county, MO
Source: F. Young, NRCS

12 Simple Fuzzy Membership model for Pierpont sinkhole areas:
High elevation (full membership above 225m) High wetness index (full membership above 5) Source: F. Young, NRCS Does an OK job of identifying areas where the sinkholes occur

13 Mapping karst in SSURGO
How can we identify karst features in… Spatial data Attribute data How might this affect interpretations? Case studies: karst in soil survey Lawrence county, IN Springfield Plateau (MLRA 116B), MO Discussion; see possible answers in last slide (AFTER discussion, please!)

14 Karst mapping: Lawrence county, IN Acknowledgements:
Dena Marshall (now Lexington KY) Genny Helt (Indianapolis IN)

15 Physiographic Features of southern Indiana (Schneider, 1966)
Source: Schneider, A.F Physiography. P in A.A. Lindsey, ed. Natural features of Indiana. Indiana Acad. Sci., Indiana State Library, Indianapolis

16 A closer look at features of the Crawford Upland & Mitchell Plain
Source: Dena Marshall, NRCS, Lexington KY A closer look at features of the Crawford Upland & Mitchell Plain

17 KY & IN Sandstone & Shale Hills & Valleys
Lawrence county - 30m DEM - MLRAs How do the lines look? Where’s the karst? Highland Rim & Pennyroyal KY & IN Sandstone & Shale Hills & Valleys

18 Physiographic Regions
Mitchell Plain: middle Mississippian- aged limestones Norman Upland Mitchell Plain Crawford Upland

19 Karst map units in Lawrence county, IN
Note: no sinkhole spot symbols

20 The karst soils in Lawrence county
“Terra rossa” Loess over “residuum” (in situ?) Crider Fi-si Typic Paleudalfs 10R w depth Knobcreek (Frederick correlated to this in IN) Fi-si / clayey Typic Paleudalfs Not as red The limestone in this area is probably too clean to have produced enough residuum in-place to create these soils.

21 Mapping patterns & rules
Limestone underlain w siltstone: little/no karst. Limestone thickens westerly; sinkholes appear. IN Geomorphology Tour “some years ago”: Karst map unit: Areas w sinkhole density of > 1 per 5 acres Spot symbol: Sinkhole density < 1 per 5 acres Ref: Pers. Comm., Dena Marshall, SS, currently Lexington KY

22 Attributes (NASIS soil properties)
Bedrock in a karst component within 80” Higher Ksat than corresponding non-karst unit Entry for Ksat in R layer E.g., Navilleton components, Floyd co IN: Karst component: R Ksat 1.42 – Non-karst component: R ksat 0.43 – 42.34 Bedrock below 80” No known differences in soil properties between karst and non-karst map units If we could populate soil property data below 80”, there would be differences.

23 MLRA Soil Survey Project: Updating Karst Areas on the Springfield Plateau (MLRA 116B)
County-based soil surveys (over 40+ years) handled karst in various ways. Ignored in some, Spot symbols in some, Karst map units in some. Inconsistent use of all of the above, both within and among counties. Springfield Plateau

24 Karst Project: Methodology
Primarily a GIS office project Utilize: Elevation data DEMs, Hypsography lines Existing SSURGO Orthophotos Sinkholes layer (statewide; USGS) On-screen digitizing/editing of SSURGO Establish new map units “Karst” in name, or Soil series that occur only in sinkhole basins.

25 Results: 20 new map units in 7 counties
“Karst” map units; e.g., Goss grsil, karst, 8-15% Sinkhole basin map units; e.g., Lowassie sil, 0-3%, freq. ponded Zoom in to this area (next slide)

26 Sinkholes point layer over 10m DEM, with SSURGO polygons

27 Map units added in this area
Blue = sinkhole basin units; Red = “Karst” in MU Name

28 Karst discussion “answers”
Spatial identification of karst: Map unit phases (i.e., “karst” in muname). Spot symbols. Map units named by components that only occur in karst (i.e., no need for “karst” in muname). e.g., in Missouri: Lowassie, Grandgulf series only occur in sinkholes. Attribute interpretation Muname contains “karst” Component geomorphic description table: landform = “sinkhole” Differences in soil properties? Interpretations Possibility for groundwater contamination Onsite wastewater disposal; lagoons; others? Not keyed in standard National Interps (?) Custom, state-created interps (e.g., MO onsite wastewater interp) Keys on “karst” in the muname, and “sinkhole” landform

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