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Infiltration under different landuse types at the Upper Ciliwung watershed of West Java, IndonesiaRachman, Seaful, n/a January 1992 (has links)
Infiltration, the process of water movement through the soil surface is one of most important hydrological processes to be considered in watershed management. The process depends on rainfall, soil, vegetation and
topographic conditions. The last three variables can be influenced by human land-uses. This study is concerned with the influence of landuse
types (categories) on infiltration at the upper
Ciliwung watershed of West-Java, Indonesia. Sixty six infiltration measurements were carried out in 5 types of land-uses i.e. natural forest, agriculture, settlement, productive (old) tea and new tea plantation areas. The measurements were done using ring infiltrometers. The data
obtained were expressed in the form of Philip's equation I = st1I2 + At, where I is cumulative infiltration; S is sorptivity; t is time; A is a parameter which was calculated from saturated hydraulic conductivity (K). Crown cover, slope gradient and soil variables such as soil moisture, organic carbon content, total porosity,
bulk density were also analysed from each of the 66 sites. The results of the study shows that land-use types have significant influence on these soil variables and on infiltration. Crown cover and human activities in term of land management are among the most important factors which affect soil condition. These variables mostly influence total porosity of soil which is the most important variable to determine sorptivity and hydraulic conductivity. High percentage of crown cover and less human activity
in forest area result in high accumulation of litter and humus and high total porosity of soil. On the other hand, settlement and new tea plantation areas have comparatively low crown cover and more frequent human activity which
result in soil compaction. Discriminant function analysis of land-use categories shows that the soil under forest is very distinct from the soils under other land-use types. However, the soils under the remaining land-use types are
more similar to each other, especially between the soil of settlement and tea plantations.
The rank of infiltration rate from the highest to the lowest magnitude is as follows; natural forest, agriculture, productive tea plantation, new tea plantation and settlement areas. Infiltration rates under natural forest and agriculture are significantly different from each
other as well as from those in the last three land- use types. However, there are no significant differences in infiltration rates among the last three land-use types. The result of this study also provides basic information
for landuse management and further research in
order to solve soil and water conservation and management problems in the watershed.
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Water Disposition in Ephemeral Stream ChannelsSammis, T. W. 06 May 1972 (has links)
From the Proceedings of the 1972 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - May 5-6, 1972, Prescott, Arizona / The contribution of flows from small watersheds to groundwater recharge is of interest. Water disposition depends on infiltration and evaporation characteristics. This study had the objective of developing an infiltration equation for estimating transmission losses during a flow event in an ephemeral stream near Tucson, Arizona, in the rocky mountain forest and range experiment station. Palo Verde, desert hackberry, cholla, marmontea and mesquite are the major bank species of the sandy channels. A climatic section consisting of a hydrothermograph recording rain gage and class a evaporation pan was installed. A water balance method was used to estimate evapotranspiration. A specially designed infiltrometer was used to simulate flow events. The data allowed the following conclusions: Philip's infiltration equation is an excellent mathematical model, initial moisture affects initial infiltration rate, the Philip coefficients are determinable by the infiltrometer constructed, soil moisture affects infiltration rates, and transpiration rates diminish linearly proportional to the ratio of available water to field capacity.
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