This is another sound scientific reason for promoting transpiration in our Redwood forest system, ag reuse and indirect discharge instead of surface water discharge.
Here is an AGU news release about a paper that will be published in Geophysical Research Letters in the near future http://www.agu.org/news/press/pr_archives/2010/2010-30.shtml
The authors estimate that transfer of groundwater into the oceans is responsible for 25% of the current rise in sea level. This is substantially greater than most previous estimates. They attribute most of the transfer to agriculture, but there is no doubt that discharging sewage into rivers that flow into the ocean is a significant contributing factor.
If the estimates in this latest paper are reasonable then the benefit of using decentralized wastewater infrastructure, with regard to preserving groundwater resources, is even more important than previously understood. http://www.nmenv.state.nm.us/fod/LiquidWaste/documents/McQuillanandBassettNOWRA09.pdf
New Mexico Environment Department