Seeing all that water going down the drain due to construction dewatering is painful. “Wait, aren’t we in a drought? And, even if we weren’t, is it right to carelessly throw water away?” But, this is a visceral reaction. We decided to look at the matter more objectively and to weigh the pros and cons of dewatering for basement construction. Our issue is not basements vs. no basements. Our concern is the construction practices used to build basements and other underground structures in areas with a high water table. Much better methods are available, and we welcome discussion with the building industry to revise Palo Alto’s Building Codes to require use of best practices that greatly reduce the amount of groundwater pumped and dumped.
In favor of dewatering we hear: “Property rights of the owner” and “it increases the value of my property”. As to property rights Save Palo Alto’s Groundwater White Paper shows that only 1- 2 % of the water that is pumped out comes from the property doing the dewatering, the rest comes from water that is under neighbors’ properties. And, those big sedimentation tanks on dewatering sites are there to catch dirt in the water (to keep it from going into the storm drains); that dirt is pulled from others’ properties by the water being pumped. Other neighbors have property rights also! As to “it increases the value of my property” we might be wrong but it seems that the most expensive real estate in Palo Alto is in the Crescent Park neighborhood. At least part of Crescent Park is in the floodplain where basements are not allowed and that hasn’t seemed to decrease the value of homes there.
Are there solid reasons to oppose dewatering? Most of us have heard the argument that this water would flow to the Bay anyway and that this water from the shallow aquifer contributes to the Bay ecosystem. All the recent articles we’ve found on groundwater depletion do not support these arguments. The Stanford Woods Institute for the Environment, states that “the indirect consequences of groundwater overdraft . . . include land subsidence and infrastructure damage, harm to groundwater-dependent ecosystems, and . . . economic losses from a more unreliable water supply for California.” Other articles say that groundwater depletion causes sea level rise (What? Instead of helping the Bay’s ecosystem we’re contributing to sea level rise?) and that groundwater depletion may trigger earthquakes, lead to food insecurity and can lead to loss of water storage capacity of our aquifers.
We made a three minute Power Point presentation to the City regarding the effects of groundwater depletion on May 2nd. Please, if the scientific evidence convinces you, join your voices in asking the City to prohibit or at the very least, minimize the amount of water that is pumped out for construction and to use all the water that is pumped, for beneficial purposes such as irrigation, dust suppression, fire suppression, etc.
Thank you for your support and advocacy!