Updating the National Updating the National Hydrography Data for Hydrography Data for the Twin Cities with the Twin Cities with
Local Subsurface Local Subsurface Drainage InformationDrainage Information
NHD Stewardship ConferenceNHD Stewardship ConferenceLakewood, Colorado April 15, 2009Lakewood, Colorado April 15, 2009
What is NHD?What is NHD?
NHD is a digital spatial dataset that NHD is a digital spatial dataset that describes the location, extent, and describes the location, extent, and relationships of surface water features relationships of surface water features for the entire nationfor the entire nation
UsesUses– Mapping water resourcesMapping water resources– Sharing/reporting of monitoring data Sharing/reporting of monitoring data
(reach ID)(reach ID)– Incorporated into watershed modelsIncorporated into watershed models
The ProblemThe Problem NHD primarily includes streams and NHD primarily includes streams and
ditchesditches Lacks feature density in urban areasLacks feature density in urban areas
NHD for ex-urban area NHD for urban area (with storm sewers)
Twin Cities Storm Water Pilot Twin Cities Storm Water Pilot Project PhasesProject Phases
Phase I: Acquire and Phase I: Acquire and Assemble Subsurface Assemble Subsurface Drainage Data from Local Drainage Data from Local GovernmentsGovernments
Phase II: Extract Significant Phase II: Extract Significant Features and Integrate into Features and Integrate into NHDNHD
Phase I: Acquiring and Phase I: Acquiring and Assembling Local DataAssembling Local Data
Acquire local data Acquire local data – Mostly CAD formatMostly CAD format
Import into GISImport into GIS Georeference Georeference Integrate into a single databaseIntegrate into a single database
There were many challenges!There were many challenges!
GeoreferencingGeoreferencing
Spatial adjustment tool used to fix georeferencing problem
Georeferenced DataGeoreferenced Data
ConnectivityConnectivity
Interrupted by other feature typesInterrupted by other feature types– maintenance access holesmaintenance access holes
Not Connected Connected
ConnectivityConnectivity
Interrupted by missing surface water featureInterrupted by missing surface water feature– DitchDitch– PondPond
DirectionalityDirectionality
Line features not digitized with Line features not digitized with directionalitydirectionality
Not Directional Directional
AttributesAttributes
Inconsistent attributes between sourcesInconsistent attributes between sources Typically limited attributesTypically limited attributes Attributes may be as graphical annotationAttributes may be as graphical annotation
Phase I: Summary of Phase I: Summary of ChallengesChallenges
Unknown coordinate systemsUnknown coordinate systems Overlapping jurisdictionsOverlapping jurisdictions Lack of directionalityLack of directionality Lack of connectivityLack of connectivity Inconsistent and sparse attributesInconsistent and sparse attributes Lack of metadataLack of metadata
Intermediate Storm Sewer Intermediate Storm Sewer Layer Results Layer Results
It was possible to assemble an It was possible to assemble an intermediate storm sewer layer. intermediate storm sewer layer.
Geo-referenced storm sewer data for 38 Geo-referenced storm sewer data for 38 communities (> 200,000 pipes)communities (> 200,000 pipes)
Only a tiny fraction will be incorporated Only a tiny fraction will be incorporated into the NHD drainage networkinto the NHD drainage network
Could be the beginning of regional storm Could be the beginning of regional storm sewer GISsewer GIS
Several significant issuesSeveral significant issues
Phase II: Incorporate into Phase II: Incorporate into NHDNHD
Select major storm water features to Select major storm water features to add to NHD (Feature Thinning add to NHD (Feature Thinning Analysis)Analysis)
Complete directionalityComplete directionality Create feature subsetCreate feature subset Use NHDGeoEdit Tools to update Use NHDGeoEdit Tools to update
NHDNHD
Feature Thinning AnalysisFeature Thinning Analysis
FactorsFactors– Area drainedArea drained
Pipe Size > 30-inPipe Size > 30-in Path lengthPath length
– Connectivity to Connectivity to currently mapped currently mapped NHD featuresNHD features
Area Covered – New Area Covered – New Features Features
Added 1078 linear drainage features Added 1078 linear drainage features (588 km)(588 km)
Features were pipelines, ditches, Features were pipelines, ditches, connectors, artificial pathsconnectors, artificial paths
Represent 6000 individual pipe Represent 6000 individual pipe featuresfeatures
Connected 363 NHD waterbodies to Connected 363 NHD waterbodies to drainage networkdrainage network
Storm Water Features – St. Storm Water Features – St. PaulPaul
Network Tracing – St. Paul Network Tracing – St. Paul
Hydrologic Unit Hydrologic Unit RedelineationRedelineation
WatershedsWatersheds– Updated major and minor watershed Updated major and minor watershed
boundaries for the Twin Cities (Mississippi) boundaries for the Twin Cities (Mississippi) major watershedmajor watershed
– Lake watershed boundaries for 113 lakesLake watershed boundaries for 113 lakes– Added attribute code to define upstream and Added attribute code to define upstream and
downstream relationshipsdownstream relationships Drainage networkDrainage network
– Enhanced network with hundreds of new Enhanced network with hundreds of new featuresfeatures
Example: Boundary Example: Boundary DisagreementDisagreement
Local hydrologic modifications may cut across the height of land boundary
DEM ReconditioningDEM Reconditioning
““Burn-in” the storm Burn-in” the storm sewer drainagesewer drainage
Adjust elevation of Adjust elevation of the digital the digital elevation model elevation model based on input line based on input line featuresfeatures
30
40
50
60
70
80
90
100
0 20
40
60
80 10
0
12
0
14
0
16
0
18
0
20
0
22
0
24
0
26
0
Lateral Distance (m)
Ele
vatio
n (
m)
Original Surface
Modified Surface
Revised DelineationRevised Delineation
ConclusionsConclusions It is possible (and useful) to use local It is possible (and useful) to use local
subsurface drainage data for update the NHDsubsurface drainage data for update the NHD NHD is a good surface water model for the NHD is a good surface water model for the
Twin Cities Metropolitan AreaTwin Cities Metropolitan Area NHD update capability was a key featureNHD update capability was a key feature NHD update tools complex to learn; docs NHD update tools complex to learn; docs
need improvementneed improvement There were many difficulties with the base There were many difficulties with the base
data (multiple sources); improving base data data (multiple sources); improving base data would improve NHDwould improve NHD
Questionable data were not added. Questionable data were not added.
Challenges of Base DataChallenges of Base Data
Multiple jurisdictionsMultiple jurisdictions Unknown coordinate systemsUnknown coordinate systems Overlapping jurisdictionsOverlapping jurisdictions Lack of directionalityLack of directionality Lack of connectivityLack of connectivity Inconsistent and sparse attributesInconsistent and sparse attributes Lack of metadataLack of metadata
SolutionSolution
Develop CAD and GIS data standards Develop CAD and GIS data standards for storm sewersfor storm sewers
Collaborative effort Collaborative effort Publish and promote the standardsPublish and promote the standards
– GuidanceGuidance– TemplateTemplate– TrainingTraining– Block grantsBlock grants
Minnesota Storm Water Minnesota Storm Water Standards Working Group Standards Working Group
Develop Exchange Standard for Digital Develop Exchange Standard for Digital Storm water System DataStorm water System Data– MPCA: MS4 Reporting & Emergency ResponseMPCA: MS4 Reporting & Emergency Response
Work through Governor’s Council on Work through Governor’s Council on Geographic InformationGeographic Information– Submit to Standards CommitteeSubmit to Standards Committee– Hydrography Committee Review Hydrography Committee Review
How does storm water guideline interact How does storm water guideline interact with surface water features?with surface water features?– Reference Existing Surface Water Data SetsReference Existing Surface Water Data Sets
CreditsCredits
Project Credits:Project Credits:
- Metropolitan Council:Metropolitan Council:- Steve KloiberSteve Kloiber- Jennifer HinzJennifer Hinz
with assistance from:with assistance from:USGS:USGS:
Paul KimseyPaul KimseyRon WenclRon Wencl
LMIC:LMIC:Sandi KuitunenSandi KuitunenJim KrumrieJim KrumrieSusanne MaederSusanne Maeder
Presentation Credits:Presentation Credits:
Steve Kloiber – MN Steve Kloiber – MN Department of Natural Department of Natural Resources (formerly Resources (formerly Metropolitan Council)Metropolitan Council)
Susanne Maeder – MN Susanne Maeder – MN Land Management Land Management Information Center Information Center (LMIC)(LMIC)
Project Funding: Project Funding:
United States United States Geological SurveyGeological Survey
http://www.metrocouncil.org/planning/environment/NHDUpdateTCMA.pdf
Questions?