There are many ways to manage storm water. Traditional or conventional methods include french drains, curtain drains, perimeter drains, dry wells, trench drains, culverts, catch basins…
These systems are designed to convey storm water underground (sub-surface) to a destination, usually a water course or subterranean chamber. Although these systems function to drain and convey water from the surface, thereby eliminating pooling, they are often invasive and expensive.
When we think about drainage we should consider the big picture. We may need a storm drain or channel drain to evacuate water from a hardscape surface in a hurry for safety or we may want to manage the sheet flow (surface water) across the grade of the entire landscape. There are many creative and sometimes even attractive ways to go about this. One way is to interrupt the grade, particularly on a steep pitch, with berms, contouring or planting beds. Bio-swales are occasionally employed as a decorative landscape feature. In addition to meeting our physical and code requirements, including sustainability, they can add interest to the landscape appearance. When using decorative gravel in a bio-swale you need to determine the flow rate. If the flow is great enough in storm events to move the gravel you may have a problem maintaining it.
Drainage Systems can pose challenges in engineering and construction yet are a necessary component for an optimally functioning landscape. If we consider water management a priority in landscape design and development we can avoid costly and sometimes plain ugly mistakes. As usual, I recommend hiring a professional to design and execute these features. Determine what your requirements are first and work with them, not around them. Integrating water management into design works well and makes sense, aesthetically, ecologically and financially.
Jay Archer, President