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To Wade Or Not To Wade? Inquiring Minds May Want To Know
Citation:
PECK, D. V. AND E. F. Smith. To Wade Or Not To Wade? Inquiring Minds May Want To Know. Presented at National Water Quality Monitoring Conference, Portland, OR, April 30 - May 04, 2012.
Impact/Purpose:
Knowing whether a steam or river site is dry, and which mode of sampling is required before visiting it to sample has important logistical implications related to scheduling equipment and field crews.
Description:
The target population for the USEPA National Rivers and Streams Assessment (NRSA) includes features ranging from headwater streams to Great Rivers. A sample frame is the spatial representation of the target population. For various reasons, a portion of the frame is non-target because the channel at the sampling point is dry. Sites are sampled by wading ("wadeable" sites) or by boat or raft ("boatable" sites). Knowing whether a steam or river site is dry, and which mode of sampling is required before visiting it to sample has important logistical implications related to scheduling equipment and field crews. We looked at dry streams identified in NRSA either before or at the time of a sampling visit, and the mode of sampling (wadeable vs. boatable), as it related to Strahler order among nine aggregated Omernik ecoregions ("regions"). Nationally (n=2,135), 10% of the sites were dry when visited. In six regions, >20% of 1st order sites were dry when visited. In the northern plains aggregated ecoregion, >20% of sites in orders 1-4 were dry when visited. For the sites sampled (n=1,960), >95% of 1st through 3rd order sites were wadeable, There was more uncertainty in sampling larger order stream sites by boat, ranging from 56-100% for 5th through 8th order sites. In the northern plains region, ≥90% of 1st-6th order streams were wadeable. In three regions, ≥90% of 1st-4th order streams were wadeable. In four regions, ≥90% of the 1st-3rd order sites were wadeable. In the northern Appalachians region, ≥90% of sites 5th order or larger were boatable. In three regions, ≥90% of sites 6th order or larger were boatable. In three other regions, ≥90% of sites 7th order or larger were boatable. Results of these comparisons focus site evaluation efforts in future monitoring studies to reduce the number of dry streams that are visited, and help determine the mode of sampling required so field crews are more efficient with sampling equipment and scheduling. This is an abstract and does not necessarily reflect EPA policy. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.