Piloting High-Resolution NHDPlus for Minnesota

Susanne MaederMinnesota Geospatial

Information Office

American Water Resources Association

GIS Specialty Conference

New Orleans, LA

March 27, 2012

Project Goals

• EPA NHDPlus v2 Design Document (EPA, USGS): – Quick to run – can

refresh Med-Res frequently

– Ability to distribute functions so that other users can create data

– Ability to build from scratch with higher-res source data

• Minnesota’s Project Goals: – Test Build of High-Res

NHDPlus v. 2 Data for Minnesota

– Understanding Data Inputs

– Understanding NHDPlus Build/Refresh v. 2 Tool

– Evaluating Results

Area of Interest

All drainage upstream of Lake Pepin, beginning

with 070101

Input Data Sets

Core Inputs: NHD, WBD, NED• High-Res NHD – rigorous editing required• WBD – 8/25/2011 version based on MN DNR

‘catchments’ layer• NED – USGS statewide 10-m DEM

Ancillary Data: Stream gages, diversions, additions, removals• Stream Gages (flow benchmarks)

– USGS NHDPointEvents/NWIS data; DNR-PCA HYDSTRA

• Large-Scale Diversions • Additions/removals (DNR Water Appropriation

Permits); consumptive use

NHDPlus v. 2 Creation Steps

Source: Horizon Systems

High-Res NHD Data Preparation

• NHDGeoEdit QA/QC Process

• NHDPlus Build/Refresh QA/QC Process

NHDUpdate/NHD GeoEditor Version 4.0- Released March 13, 2012- Full NHDPlus Build/Refresh QA/QC Tools? - Only runs on NHD Model 2.1(ComID issue)

NHD Data Preparation Issues

• NHDPlus Build/Refresh QA/QC– Need to be able to unequivocally identify the

main flow path and construct a traversable flow network

– GNIS names are very important– Ensure calculation of VAA values– Potential severe errors:

• Flow table entry never navigated; improper network end; invalid or duplicate flow table entry; potential loop; incomplete divergence

– Warnings/ informational errors:• Isolated network; circular named path,

possible inflowing connection

NHD Data Preparation – Selecting Main Path

• PlusFlowlineVAA

• DivFracMP

NHD Data Preparation – Selecting Main Path

Questions?

Lake Itasca State Park – Headwaters of the Mississippi

Photo Source: Minnesota Department of Natural Resources