Digital computer solutions of groundwater flow

This paper examines critically the use of the alternating direction implicit method for solving groundwater flow problems. Comparisons with alternative solutions show that inaccuracies can arise if the time increments are too large. A method is suggested whereby the computer chooses an optimum time increment. The representation of recharge, infiltration and wells is considered and a detailed example compares the alternating direction implicit, the explicit and the resistance-capacitance network methods.     

黄金岸线海滩能否抵挡极端事件的冲击

砂质海滩是最变化莫测和脆弱的海岸带类型之一。众所周知,海滩在高能环境中会被侵蚀,但海滩上不同位置点对于极端事件的抵御能力则大不相同。而且,侵蚀速率通常受控于海滩状况、机械结构和前期补给。     

Peat deposit water quality in Lake Istokpoga,Florida, U.S.A.

In 1983 water quality monitoring was conducted on peat deposits in Highlands County, Florida, U.S.A. The monitoring objective was to provide initial data on the water quality in the area in order to identify potential problems with environmental licensing of peat harvesting operations on these deposits. The investigation included sampling for in situ and laboratory water analyses, peat core analyses, elutriate tests, and interstitial water quality analyses. The general trends evident from the data are that BOD and COD (and the resulting DO) may change from the control and harvest peatlands, but not consistently. In addition, total suspended solids, organic color, total nitrogen, and total phosphorus concentrations appear to be elevated under disturbed conditions. For metals, the major cations (Ca, Mg, K, Fe) may show an increase under disturbed conditions vs. control. For the remaining metals, some increases may occur, but the changes are essentially unpredictable.