Fetch Wieczorek et al. NHDPlusv2 attributes

[lekoenig]

Download the following datasets from the Wieczorek et al. data releases on ScienceBase:

• [x] stream density and sinuosity (data release)
• [x] statsgo soil texture and layers (data release). These data are already downloaded/included in our pipeline, but we could add these data to the download process we use to access multiple Wieczorek data releases
• [x] 30-yr mean annual precipitation (data release)
• [x] rock hydraulic conductivity, i.e. OLSON_PERM (data release)
• [x] baseflow index (data release)
• [x] subsurface flow contact time index (data release)
• [x] mean annual natural groundwater recharge (data release)
• [x] topographic wetness index (data release)
• [x] average depth to water table (data release)
• [x] basin slope (data release)
• [x] average stream slope (data release)

Other datasets that may be useful but are not higher priority:

• [x] bedrock permeability classes (data release)
• [x] county-level freshwater withdrawals (data release)
• [x] percent land in irrigated agriculture (data release)
• [x] NLCD impervious cover (data release)
• [x] Hydrologic group A soils (data release)
• [x] soil permeability and depth to seasonally high water table (data release)
• [x] soil percent sand (data release) Check whether these data have already been downloaded as part of the STATSGO variables