The following is a list of items which can help to improve the
performance and stability of your hillside property. Maintenance
of your hillside property is the responsibility of the individual
property owner.
Drainage
Possibly the most important item in maintaining a hillside property is proper drainage control. All existing structures should be provided with roof gutters which discharge into downspouts. The roof drainage should then be transferred to the paved street or storm drain in nonerosive drainage devices, such as PVC pipe. Roof drainage must not be allowed to discharge adjacent to the foundation system. Pad and yard drainage should be collected by area drains which also transfer runoff to the street or storm drain system. Drainage must not be allowed to pond on the pad, against any foundation or behind retaining walls. Slope drainage should be collected in a system of paved surface drains. Slope drainage must not be allowed to flow uncontrolled over any descending slope. It is important for the hillside property owner to periodically inspect all drainage devices. Broken or nonfunctional devices should be repaired immediately. Cracks should be properly sealed. Seasonal cleaning is also required in order for the devices to function properly.
Erosion Protection
Erosion of slopes in the hillside area is a common problem. While erosion can not be completely prevented, certain precautions and mitigating measures can be taken to limit the amount of slope erosion. The most effective preventative measure is proper drainage control. Where possible, all slopes should be planted with approved vegetation. Proper planting will not eliminate the risk of slope failure and slumping within the upper three feet of surficial slope materials, however the root structure can help to impede erosion. Unplanted slopes should be covered with plastic during the rainy season.
Debris Protection
Structures located within the axes of natural drainage courses are subject to hazards resulting from concentrated runoff and mudflow. Proper protection devices include retaining walls, deflection walls and surface drains. Retaining walls and deflection walls should be provided with sufficient freeboard to prevent debris from overtopping the wall during intense rainfall periods. A paved "V" drain is commonly constructed behind protective walls to channel debris and runoff to the street or approved location. The surface drain requires periodic cleanout of debris in order to remain effective. Inspection of the wall and drains should also be made for any signs of cracking or distress. Cracks should be properly sealed.
Landscape Watering
Another common problem in the hillside area is overwatering of landscape areas. Overwatering leads to accelerated erosion of slopes, saturation of surficial materials and slope failure. Slopes and landscape areas should be carefully monitored for moisture content. Care should be taken not to overwater. A regulated watering system with timers is recommended. Periodic inspection of the watering system should be performed to check for leaks and breaks in the lines. All leaks and breaks should be immediately repaired.
Rodent Control
Burrowing animals, such as gophers can cause slope stability problems. Animal burrows loosen the soil and provide conduits for surface runoff which often leads to accelerated erosion and mudflows. Extermination of all burrowing animals present on the site is recommended.
