Water may flow onto your property from an adjacent lot because of natural topography, meaning that your lot is at a lower elevation, or servient, to the upland or dominant property. You cannot change that flow to the detriment of the owner of the higher property. You must continue to accept water which flows naturally from properties located at higher elevations, but you can make improvements on your property to control and redirect the water with a drainage system on your property. The engineering department can make suggestions to help your situation, but a more complex plan will require the services of a design professional and possibly a permit from the engineering department.
If the owner of the higher property alters conditions on his or her land which increases the burden of the water flowage onto the lower property, the engineering department will work with the upland owner and/or contractor to remedy the condition.