223A

Observed differences in soil moisture within the unsaturated zone result from the interaction of surface-water inputs with spatially inhomogeneous soil characteristics. Water which ini- tially percolates vertically is differentially impeded as a result of texture changes in the soil, with water being preferentially retained in such zones of transition. The scale of this vertical variability is of teaths of metres compared with lateral vari- ability over a few metres. It is suggested that the assumptions of isotropy and homogeneity used in drainage and slope hydro- logical models should be re-examined.

Groundwater

846151 Effects of groundwater geochemistry on the permeability of grouted fractures Gale, J E; Reardon, E J Can Geotech J V21, NI, Feb 1984, P8-20

Permeability tests were carried out at different confining pre- ssures on a granite core containing a natural fracture running parallel to the core axis. The fracture was then grouted with Por- tland cement and allowed to cure for 40 days. Distilled water was forced through the sample until a significant flow rate developed. The influent solution was changed twice to examine the effect of differing concentrations of calcium bicarbonate solution. The permeability of the fracture plane decreased over several months as a result of calcite precipitation. After the test the core was opened along the fracture plane. The fracture ex- hibited 2 channels coated with precipitated calcite. The quantity of precipitate was in reasonable agreement with calculated amounts.

846152 Investigation of aquifer parameters using multiple piezometers Walthall, S; Ingrain. J A Ground Water V22. NI, Jan-Feb 1984, P25-30

In order to investigate the parameters of the North Merseyside Permian-Triassic Sandstone Aquifer, a special observation borehole was drilled, developed and tested. Six standpipe piezometers were installed to investigate the distribution of piezometric head within the aquifer and the response during pumping tests. The investigation shows that misleading results can be obtained using a single open borehole unless the pro- cesses in the aquifer are understood; this is reflected in the variety of results obtained using conventional tests.

846153 Observed drawdown pattern around a well partially penetrating a vertically extensive water-table aquifer Sayed, S A S Ground Water V22, N2, March-April 1984, P148-153

A specially designed pumping test was carried out in Pakistan to understand the flow pattern around a pumping well partially penetrating a vertically extensive aquifer. It was concluded from the drawdown pattern that the distance beyond which the flow is likely to be horizontal increases with decrease in the degree of aquifer penetration. In equidistant observation wells open at different depths: (1) the drawdowns tend to merge at larger times, provided the observation point is located within the screened section of the aquifer; (2) the less the depth of penetra- tion the earlier the drawdowns start merging; and (3) the initial rate of drawdown near the aquifer top is slow, but catches up with time to exceed those at deeper points.

84~IM Analysis of conceptual designs for remedial measures at Lipari Landfill, New Jersey Andersen, P F; Faust, C R; Mercer, J W Ground Water V22, N2. March-April 1984, P176-190

A finite difference model was used to evaluate the relative effec- tiveness of alternative remedial measures for the Lipari Landfill, a hazardous waste site. These include: (1) a slurry cut off wall, (2) a drain, and (3) a low-permeability cap. Sensitivity analyses were performed on several design criteria: (1) drain existence, (2) drain depth, (3) drain location, (4) drain length, (5) slurry wall existence, (6) slurry wall length, and (7) cap extent. The analysis quantified discharge to drains, flow rates to a swamp downstream of the landfill, time required to drain the landfill and contaminant travel times that would result from the im- plementation of each of the remedial measures suggested.

846155 Groundwater recharge through a heavy-textured soil Hendry, M J J Hydrol V63. N3-4, June 1983, P201-209

A test hole was cored to a depth of 17.4m into glacial till in Southern Alberta, Canada and samples were collected from the cores at 0.3m intervals. The soil water was distilled and analysed for tritium which would be present in water entering the sub- surface after 1953, due to nuclear testing. The samples were also analysed for particle size distribution. The tritium data showed that post-1953 recharge water had migrated down to the lacustrine-till contact area by intergranular seepage and frac- ture flow.

846156 Unsteady flow against dispersion in finite porous media Kumar, N J Hydrol V63, N3-4, June 1983, P345-358

Analytical solutions are presented for dispersion in a finite non- adsorbing and adsorbing porous medium. A new time variable is introduced to solve the unsteady flow problem.

846157 Modeling moisture and thermal transport in unsaturated porous media Yeh, G T; Luxmoore, R J J Hydrol V64, NI-4. July 1983. P299-309

A multi-dimensional computer code using the integrated com- partment method was developed to simulate the behaviour of Philip-de Vries equations governing simultaneous moisture and heat flows in unsaturated aquifer systems.

846158 Pmping tests using large-diameter observation wells Barker, J A J Hydrol V67, N1-4, Jan 1984, P375-379

The drawdown in a large-diameter observation well during a pumping test, using a production well of negligible diameter, is shown to be identical to the drawdown that would be observed if the roles of the wells were reversed.

846159 Investigation of the principles of operation of the heat-pulse flowmeter Tselentis, G A J Hyc&ol 1/69, N1-4, 10 Feb 1984, P335-349

A new type of instrument, the heat-pulse flowmeter has been used recently for velocity measurements as low as 5mm/s. This paper investigates the principles of operation of a similar device and discusses the results of some experimental investigations.