The Christina River Basin Critical Zone Observatory (CRB-CZO) was established in 2009 as a community platform for research on critical-zone processes, and is based on a strategic partnership between the University of Delaware (UD), the Stroud Water Research Center (SWRC) and numerous other organizations.

We are one of six NSF-supported environmental observatories focusing on the "Critical Zone": where water, atmosphere, ecosystems, and soils interact and shape the Earth's surface.

Unique Aspects of CRB-CZO:

• Located in the Piedmont and Atlantic Coastal Plain physiographic provinces, and includes satellite coastal sites along the Delaware Estuary.

• Diverse human land use for centuries.

• Drinking water source to a million+ people in Northern Delaware and Southeastern Pennsylvania.

• Exceptionally well studied by USGS, SWRC, EPA and numerous local agencies
Historical Datasets.

The Christina River Basin and its four sub-basins may be one of the best studied watersheds of its size in the nation. Studies include seminal fluvial geomorphology or the Brandywine Creek by Luna Leopold, >100 peer-reviewed publications by the Stroud Water Research Center, and extensive long-term monitoring efforts by EPA, USGS and others maintaining quality water supplies to one million people and developing Total Maximum Daily Load regulations. Within the CRB, there are 19 USGS stream/river gauging stations (6 in DE, 13 in PA) and 5 of the PA stations continuously monitor water quality properties (i.e. turbidity, pH, conductivity, dissolved oxygen). SWRC has historically maintained continuous discharge and other datasets at 3 stations. Non-continuous data collected by USGS and SWRC are available for 141 stations. Weather data has been continuously recorded by 5 USGS stations and a NOAA Climate Reference Network station.