<li>Although linear design (surface area typically >2:1 length:width) is a feature of a swale, an absolute minimum width is 0.6 m is required for bioswales to have healthy plant growth, and to facilitate construction. </li>
<p>Although linear design (surface area typically >2:1 length:width) is a feature of a swale, a minimum width is 0.6 m is recommended to have healthy plant growth and to facilitate construction. </p>
<li>Grassed swales are usually mown as part of routine maintenance, so the cross section will be parabolic or trapzoidal in shape. The minimum width for this type is 2 m. </li>
<li>Swales may be graded along longitudinal slopes between 0.5 - 6 %.</li>
<ul>
<li>Check dams are required on slopes > 3 %. </li>
<li>Slopes > 6% can accommodate a series of stepped [[bioretention cells]], each overflowing with a weir, into the next. </li>