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NOTE: To get off this list, send email to majordomo@aqua.ccwr.ac.za with the body of the message containing the line: unsubscribe sowacs Dear Trisha No one else has responded concerning the "reality" of underground streams, so I guess I will. The mention of "underground streams" makes most hydrogeologists "wince." What you are most likely experiencing is a rising water table caused by a wet precipitation pattern/cycle or local infusion to the ground-water by irrigation or poor surface drainage. That the water is entering from one direction probably indicates 1) this is the portion of the basement that has the most assessible crack or 2) lowest elevation or 3) this is the location where the ground water has the highest elevation. The gradient of the ground water "table" may be from the direction of the leak, but it may not be. Technically, "underground rivers" occur only as large conduits in Karstic geology, i.e, limestone formations where some of the limestone has dissolved over time leaving conduits. These may also occur in some basalt or rhyolite (i.e., lava flow) formations where lava tubes conduct large amounts of water. These situations occur in only a few parts of the US and I do not believe that Long Island is one of these. In any case, we usually do not subscribe the term underground river to these situations. Rather than spending time attempting to locate this underground river and then figuring out means for subduing it, I suggest the following course of action: 1) wait until the wet precipitation cycle has ended. The water table will probably drop and your basement will dry (do this free alternative if you have time and patience) 2) search your local area (within about 1/10 mile) and look for sources that may be adding water to the groundwater. For example, a broken city water main, a lot where rainfall runoff is ponded and infiltrates the ground, a backed up storm sewer, a neighbor (or yourself) who has left the lawn sprinkler system or hose running for long periods of time. You may wish to call the local city officials to ask them to confirm the lack of leakage of water from the city water system in your area. 3) If the problem appears to be one that will be chronic, then you may have to consider excavating around the outside of your basement and foundation or inside the basement and installing some type of drainpipe and a pump or means to connect the drainpipe into the city sewer system (if this is allowed). This is a pricy option, but is effective. To conclude, I would bet against an underground river and for a rising ground water table, which means simply that the ground below your home has become saturated to a higher elevation. Rick Allen Prof Water Resources Engineering Univ. Idaho > > Trisha, > > About seventeen years ago my aunt had an encounter with the same stream. > She was a principal of a high school in the area and the encounter involved > problems with settlement of the basement slab in one of their buildings. I > would recommend that you contact a local geotechnical engineering firm that > is familiar with the problem since you may have to deal with a lot more than > a flooded basement. You could start by calling the Civil Engineering > Department at Brooklyn Polytech for some guidance. > > Sincerely, > Kevin O'Connor > > > > > At 06:14 PM 3/5/00 GMT, you wrote: > >>Dear Bruce, > >> I came upon your site while researching underground streams. I live in Park > >>Slope, Brooklyn, NY and there are many in the neighborhood. It seems that > >>recently one has surfaced under my house in the ground below the basement > >>floor. I'd like to install a sump pump, but first, I'd like to be able to > >>determine which direction the water is coming from. Is there an electrical > >>device or sonar device available to trace the origin of the water? Your > >>input would be greatly appreciated. Thank you. > >>Regards, > >>Trisha > >>Reply via e-mail to trisha@brooklynproperties.com > >> > >> > >> > ++++++++++++++++++++++++++++++++++++++++++++++++++ > > Kevin O'Connor, Ph.D. (612) 431-3415 voice > GeoTDR, Inc. (612) 892-0241 fax > 297 Pinewood Drive kevin@geotdr.com > Apple Valley, MN 55124 http://www.geotdr.com > > +++++++++++++++++++++++++++++++++++++++++++++++++ > > > >