Laserfiche WebLink
<br />,, <br />Grassed waterways <br />These are waterways shaped or graded and established 1n suitable <br />vegetation to dispose of runoff water without damage by erosion. <br />This practice applies to sites where added capacity and/or <br />vegetative protection is required to control erosion resulting <br />from concentrated runoff. Supplemental measures may be required <br />' such as grade control structures and rubble or log lined channel <br />bottoms. Design capacity should accommodate peak runoff from a <br />minor frequency storm. Design velocity is based on soil type, <br />' duration of flow, and type and quantity of vegetation. <br />Straw Mulching <br />' Bare, non-vegetated slopes can erode quickly and should be <br />vegetated if final reclamation does not follow in the same <br />season. Straw mulching may be broadcast by hand, and aids in <br />' establishing good vegetative cover and provides temporary erosion <br />control until sufficient plant cover develops. On steep slopes, <br />or where exposed to strong winds, mulch should be secured to <br />prevent its being washed or blown away. This can be done by <br />spraying with asphalt or chinking in with a light disk, neither <br />of which interferes with seedling growth. <br />' Rubble Line Channels <br />where concrete rubble is available, rubble lined channels are an <br />' efficient method of permanent erosion control. Logs may also be <br />used to stabilize channels. The logs should be a minimum of <br />eight inches in diameter and placed perpendicular to the water <br />flow. Used in combination with vegetative side slopes, the <br />rubble or log section is to designed to handle the greater of <br />either the base flow or runoff from a one-year frequency storm. <br />Flow depth of the rubble section shall be a minimum of .5 feet. <br />' Rock size used is dependent of the channel design depth and <br />slope. Logs of sufficient diameter may be used in conjunction <br />with rubble. <br />Straw Bale Sediment Check Dams <br />Constructed with straw bales for low head situations, a detention <br />' storage area is created which detains storm water. The primary <br />function of the dam is to intercept and detain sediment laden <br />flow long enough to allox the larger sized particles to settle <br />out prior to passage of runoff to downstream areas. Other <br />' functions include storage of the deposited sediment, reduction of <br />the peak flow rate, and diversion to a non-erosive charnel. <br />Bales deteriorate within 3 to 6 months and are, therefore, only a <br />~ : temporary control measure. <br />E-2 <br /> <br />