Loosen matching criteria on larger streams

[limnoliver]

While digging into #29, I found some instances of sites being dropped due to violating the maximum bird distance, when in reality, these sites were right at the edge of very large streams (e.g., lower Delaware where stream is >500m wide, thus our 250m max distance is too small).

Here is a satellite image of the example gage location and stream (site 01467059), which gets dropped with our current setting of bird distance < 250m.

[aappling-usgs]

Good find!