This looks like a millipede. Check the web links below and see if this is consistent with what you are seeing. If these are indeed millipedes, they generally feed on decaying matter in our landscapes and generally stay in moist areas. Do you have a lot of damp decaying material in the your yard or around the outside of your home near where you are seeing them? If yes, one method of control would be removing what you can of this material, or at least from areas immediately near your home where it matters most. If you are watering your lawn regularly - does it have time between to dry out or is it regularly damp around the perimeter of your home? Allowing it to dry some between waterings, particularly near foundation can help. It is likely that the river water contains organic material as well but I am unsure whether this impacts your insect situation or not. To keep milipedes from your home, sealing gaps or openings can help, in addition to the removal of extra decaying material near your home (leaves, plant materials, mulch etc). A dehumidifier in your home may be useful if the millipedes are being drawn to a damp space once in your home. Otherwise, they will tend to die relatively quickly in dry indoor conditions. If you choose to use chemical controls, review the linked websites for information for choosing one that is suited for the outside foundation of your home. Your current product may not contain the necessary ingredients for millipede control. http://www.ipm.iastate.edu/ipm/iiin/mmilliped.html http://www1.extension.umn.edu/garden/insects/find/sowbugs-millipedes-centipedes