Reference hydrologic networks I: the status and potential future directions of national reference hydrologic networks for detecting trends

Identifying climate-driven trends in river flows on a global basis is hampered by a lack of long, quality
time series data for rivers with relatively undisturbed regimes. This is a global problem compounded by the lack
of support for essential long-term monitoring. Experience demonstrates that, with clear strategic objectives, and
the support of sponsoring organizations, reference hydrologic networks can constitute an exceptionally valuable
data source to effectively identify, quantify and interpret hydrological change—the speed and magnitude of which
is expected to a be a primary driver of water management and flood alleviation strategies through the future—and
for additional applications. Reference hydrologic networks have been developed in many countries in the past few
decades. These collections of streamflow gauging stations, that are maintained and operated with the intention of
observing how the hydrology of watersheds responds to variations in climate, are described. The status of networks
under development is summarized. We suggest a plan of actions to make more effective use of this collection of
networks.