Idaho’s Experience with Random Design using NHD Intermittent streams and other considerations Mary Anne Nelson, Michael McIntyre, Michael Edmondson, Glen Pettit Idaho Department of Environmental Quality

Sampling Design Sample Population –All perennial, wadeable streams –1:100,000 scale Sampling Frame –NHD supplied to ORD (Corvallis, OR) –Strahler order (1-5) –DEQ Region Survey Design –Generalized random tessellation stratified survey design for a linear network

Multi-Density Categories –DEQ Regions (6) –Strahler Order 1&2 (50%) 3 (30%) 4&5 (20%) Panels: 5 panels of 50 sites statewide, 1 panel monitored each year 500% Oversample Sampling Design

Site Selection Wadeable vs. Non-Wadeable –4 th order or less –Less than 15 m average wetted width –Less than 0.4 m average depth at base flow Inaccessible –Minimum 2 hour hike to access –Safety issues Dry Wetland/No Flow Denied Access Impoundments –Beaver dams Map Error Where rubber meets the road

Accessibility

Flow

Monitoring Effort in 2004  56 Random Sites (8.5%)  220 Rejected Random Sites (33.38%)  238 Target Sites (36.12%)  104 Rejected Target Sites (15.78%)  6 Random Repeat (0.91%)  35 Reference Trend (5.31%) Total Sites % Effort in Random Sites % Effort in Targeted Sites

50 Primary Sites 250 Secondary Sites 56 Monitored Random Sites 2004 Site Selection Results Of the 50 Primary Sites 11 Monitored 32 Rejected 7 unknown

2004 Rejected Random Sites 116 Not Visited 104 Visited 54INACCESSIBLE69DRY 29ACCESS DENIED10NON WADEABLE 15NON WADEABLE7NO FLOW 8DRY4ACCESS DENIED 4NO FLOW4WETLAND 3T & E SPECIES3ALTERED 1 3INACCESSIBLE 1MAP ERROR3 1 TEMP INACCESSIBLE1NORMAL 220 Rejected Sites in 2004

Monitoring Effort in 2005  49 Random Sites (12.16%)  187 Rejected Random Sites (46.40%)  109 Target Sites (27.05%)  22 Rejected Target Sites (5.46%)  6 Random Repeat (1.49%)  30 Reference Trend (7.44%) Total Sites % Effort in Random Sites % Effort in Targeted Sites

89 Not Visited 98 Visited 30INACCESSIBLE58DRY 26DRY9DENIED ACCESS 11ACCESS DENIED9HIGH FLOW 10LIMITED ACCESS8NO FLOW/WETLAND 9NON-WADEABLE7INACCESSIBLE 2NO FLOW3UNKNOWN 1NO DATA2BEAVER COMPLEX 1LIMITED ACCESS 1NO RIFFLES 2005 Rejected Random Sites 187 Rejected Sites in 2005

Dry Sites in Idaho

Monitored Sites in Idaho

Precipitation 2004 Monitored Sites 2005 Monitored Sites 7-10” ” ” ” ” ”21 77 Sites Rejected in 2004 as Dry 84 Sites Rejected in 2005 as Dry

Public Lands Sites on Private Land Monitored Access Denied Sites on Public Land Land TypeAcres Federal33,764,664 Private16,387,873 State2,615,417

Breakdown of Land Ownership PrivatePublic Land %30.99%68.79% 2004 Sites Monitored 32.14%67.86% 2005 Sites Monitored 30.61%69.39%

Landuse Patterns Dryland Ag40 Forest3531 Irrigated- Gravity 32 Irrigated- sprinkler 31 Rangeland13 Urban02

GIS Site Analysis GIS coverages –Precipitation –Land Use Satellite imagery –NAIP imagery –Vegetative Cover Catchment area –ArcGIS Spatial Analyst –USGS StreamStats

Conclusions To achieve the required 50 sites/year, roughly 200 sites were rejected –31 % of sites are dry –23 % of sites are inaccessible Need to improve NHD coverage to address intermittent and ephemeral waters Working on low-flow model with USGS Assessment of these sites to be carried out in May 06 for inclusion in the 06 integrated report