Spatial designs for monitoring stream networks, especially ephemeral systems,
are typically non-standard, `sparse' and can be very complex, reflecting the
complexity of the ecosystem being monitored, the scale of the population, and
the competing multiple monitoring objectives. The main purpose of this paper is
to present a review of approaches to spatial design to enable informed
decisions to be made about developing practical and optimal spatial designs for
future monitoring of streams.Comment: Published in at http://dx.doi.org/10.1214/07-SS032 the Statistics
Surveys (http://www.i-journals.org/ss/) by the Institute of Mathematical
Statistics (http://www.imstat.org