ABSTRACT
Ti ¼ 1 exp½VsiL=q ð1Þ
where q is the specific discharge and L is the length of the pond (Fig. 1). When the ponded area retains significant transport capacity, trapping efficiency is reduced and a transport capacity or sediment re-entrainment term must be added.[4]
Increased Infiltration of Water into Soil
Vegetation increases infiltration by: 1) reducing the development of surface seals that limit infiltration rates; 2) increasing soil water storage capacity through evapotranspiration; and 3) developing soil macroporosity through root growth and enhanced activities mesofauna such as earthworms and ants. By covering the soil and absorbing the kinetic energy of raindrops, vegetation can prevent the detachment and rearrangement of soil particles that result in the creation of soil seals[5] and thus increases infiltration. Although water use varies with species and climate, vegetation transpires approximately 0.3m3 of water for each kg of above-ground dry matter produced.[6] This transpiration leaves more capacity in the soil for infiltration of subsequent rains and thus reduces runoff and erosion.[7] Vegetation increases soil macroporosity directly through root growth[8] and indirectly by improving the habitat and activity of mesofauna.[9] By slowing runoff,
El N in˜ o-
Ev ap
or at io n
vegetation increases the depth of ponded water and the area of soil that that is submerged, thus increasing opportunities for macropore flow.
