Thomas M. Missimer

Arid lands water evaluation and management

From the Contents: Aridity and Drought.- Geology of Arid Lands.- Aquifer Concepts in Arid Lands.- Introduction to Aquifer Hydraulics.- Water Budget.- Precipitation and Evapotranspiration.- Recharge Concepts and Settings.- Sustainability and Safe Yield.- Assessment of Groundwater Resources.- Recharge Measurement in Arid and Semiarid Regions.- Environmental Isotopes.- Wadi Recharge Evaluation.- Microgravity.- Compaction and Land Subsidence.- Surface and Airborne Geophysics.- Borehole Geophysical Techniques.- Remote Sensing.- Geographic Information Systems.- Groundwater Flow and Solute-Transport Modeling.- Ancient Water Management.- Rainwater, Stormwater, and Fog Harvesting.- Managed Aquifer Recharge.

Unusual calcite stromatolites and pisoids from a landfill leachate collection system

Low-magnesium calcite stromatolites and pisoids were found to have precipitated within the leachate collection system piping of a Palm Beach County, Florida, landfill. The stromatolites and pisoids formed in an aphotic and anoxic environment that was at times greatly supersaturated with calcite. The stromatolites are composed of branching cylindrical bundles of concentrically laminated radial fibrous crystals. The pisoids consist of concentric layers of radial fibrous and microcrystalline calcite. Bacteria, likely sulfate reducing, appear to have acted as catalysts for calcite crystal nucleation, and thus the formation of the stromatolites and pisoids. The leachate system stromatolites provide a recent example of stromatolites that formed largely by cement precipitation. By acting as catalysts for calcite nucleation, bacteria may cause more rapid cementation than would have occurred under purely abiotic conditions. Rapid calcite precipitation catalyzed by bacteria has interfered with the operation of the Palm Beach County landfill leachate collection by obstructing pipes and may be an unrecognized problem at other landfill sites.

Determination of Hydraulic Conductivity from Grain-Size Distribution for Different Depositional Environments

Over 400 unlithified sediment samples were collected from four different depositional environments in global locations and the grain-size distribution, porosity, and hydraulic conductivity were measured using standard methods. The measured hydraulic conductivity values were then compared to values calculated using 20 different empirical equations (e.g., Hazen, Carman-Kozeny) commonly used to estimate hydraulic conductivity from grain-size distribution. It was found that most of the hydraulic conductivity values estimated from the empirical equations correlated very poorly to the measured hydraulic conductivity values with errors ranging to over 500%. To improve the empirical estimation methodology, the samples were grouped by depositional environment and subdivided into subgroups based on lithology and mud percentage. The empirical methods were then analyzed to assess which methods best estimated the measured values. Modifications of the empirical equations, including changes to special coefficients and addition of offsets, were made to produce modified equations that considerably improve the hydraulic conductivity estimates from grain size data for beach, dune, offshore marine, and river sediments. Estimated hydraulic conductivity errors were reduced to 6 to 7.1 m/day for the beach subgroups, 3.4 to 7.1 m/day for dune subgroups, and 2.2 to 11 m/day for offshore sediments subgroups. Improvements were made for river environments, but still produced high errors between 13 and 23 m/day.

Use of beach galleries as an intake for future seawater desalination facilities in Florida and globally similar areas

AbstractDesalination of seawater using the reverse osmosis process can be made less costly by the use of subsurface intake systems. Use of conventional open-ocean intakes requires the addition of a number of pretreatment processes to protect the primary RO process. Despite using the best designs possible for the pretreatment, seawater RO membranes tend to biofoul because of the naturally-occurring organic material and small bacteria present in seawater. These materials are not completely removed by the pretreatment system and they pass through the cartridge filters into the membranes, thereby causing frequent and expensive cleaning of the membranes. Quality of the raw water can be greatly improved by the use of subsurface intakes which can substantially reduce the overall treatment cost. There are a number of possible subsurface designs that can be used including conventional vertical wells, horizontal wells, collector wells, beach galleries, and seabed filters. The key selection criteria for the type of ...

Restoration of Wadi Aquifers by Artificial Recharge with Treated Waste Water

Fresh water resources within the Kingdom of Saudi Arabia are a rare and precious commodity that must be managed within a context of integrated water management. Wadi aquifers contain a high percentage of the naturally occurring fresh groundwater in the Kingdom. This resource is currently overused and has become depleted or contaminated at many locations. One resource that could be used to restore or enhance the fresh water resources within wadi aquifers is treated municipal waste water (reclaimed water). Each year about 80 percent of the countrys treated municipal waste water is discharged to waste without any beneficial use. These discharges not only represent a lost water resource, but also create a number of adverse environmental impacts, such as damage to sensitive nearshore marine environments and creation of high-salinity interior surface water areas. An investigation of the hydrogeology of wadi aquifers in Saudi Arabia revealed that these aquifers can be used to develop aquifer recharge and recovery (ARR) systems that will be able to treat the impaired-quality water, store it until needed, and allow recovery of the water for transmittal to areas in demand. Full-engineered ARR systems can be designed at high capacities within wadi aquifer systems that can operate in concert with the natural role of wadis, while providing the required functions of additional treatment, storage and recovery of reclaimed water, while reducing the need to develop additional, energy-intensive desalination to meet new water supply demands.

Combined desalination, water reuse, and aquifer storage and recovery to meet water supply demands in the GCC/MENA region

Abstract Desalination is no longer considered as a nonconventional resource to supply potable water in several countries, especially in the Gulf Corporation Countries (GCC) and Middle East and North Africa (MENA) region as most of the big cities rely almost 100% on desalinated water for their supply. Due to the continuous increase in water demand, more large-scale plants are expected to be constructed in the region. However, most of the large cities in these countries have very limited water storage capacity, ranging from hours to a few days only and their groundwater capacity is very limited. The growing need for fresh water has led to significant cost reduction, because of technological improvements of desalination technologies which makes it an attractive option for water supply even in countries where desalination was unthinkable in the past. In the GCC/MENA region, operating records show that water demand is relatively constant during the year, while power demand varies considerably with a high peak ...

Aridity and Drought

Aridity is a term that most people conceptually understand, and it evokes images of dry, desert lands with sparse natural surface-water bodies and rainfall, and commonly only scant vegetation, which is adapted to a paucity of water.

Sustainable renewable energy seawater desalination using combined-cycle solar and geothermal heat sources

Abstract Key goals in the improvement of desalination technology are to reduce overall energy consumption, make the process “greener,” and reduce the cost of the delivered water. Adsorption desalination (AD) is a promising new technology that has great potential to reduce the need for conventional power, to use solely renewable energy sources, and to reduce the overall cost of water treatment. This technology can desalt seawater or water of even higher salinity using waste heat, solar heat, or geothermal heat. An AD system can operate effectively at temperatures ranging from 55 to 80°C with perhaps an optimal temperature of 80°C. The generally low temperature requirement for the feedwater allows the system to operate quite efficiently using an alternative energy source, such as solar power. Solar power, particularly in warm dry regions, can generate a consistent water temperature of about 90°C. Although this temperature is more than adequate to run the system, solar energy collection only can occur during...

Skeletal aragonite neomorphism in Plio-Pleistocene sandy limestones and sandstones, Hollywood, Florida, USA

Abstract The basic mechanics of the neomorphism of aragonitic shells to calcite are generally understood, but fundamental questions remain concerning the details of the process. Completely and partially neomorphosed aragonitic skeletal fragments recovered in cores of Plio-Pleistocene limestones and sandstones from Hollywood, Florida, provide some insights into the process. Skeletal aragonite neomorphism occurred in a volume for volume manner across solution films, which resulted in the preservation of ghosts of fine-scale microstructures. Neomorphic calcite crystals that replaced skeletal aragonite in at least some instances inherited their crystallographic orientation from adjoining calcite cement crystals rather than from the host shell microstructure. Some neomorphic calcite crystals inherited the optical orientation of nearby echinoderm ossicles. However, host shell microstructure commonly controlled the direction of migration of the neomorphic replacement front. Anisotropies in shell solubility influenced the directional rates of growth of neomorphic calcite crystals, as evidenced by the strong tendency for the boundaries between neomorphic calcite and aragonite to parallel or coinicide with shell microstructural features. No examples were observed where neomorphic calcite replaced aragonite along euhedral crystal faces, such as commonly occurs during dolomitization and the replacement of limestone by megaquartz.

Estimation of soil salinity in a drip irrigation system by using joint inversion of multicoil electromagnetic induction measurements

Low frequency electromagnetic induction (EMI) is becoming a useful tool for soil characterization due to its fast measurement capability and sensitivity to soil moisture and salinity. In this research, a new EMI system (the CMD mini-Explorer) is used for subsurface characterization of soil salinity in a drip irrigation system via a joint inversion approach of multiconfiguration EMI measurements. EMI measurements were conducted across a farm where Acacia trees are irrigated with brackish water. In situ measurements of vertical bulk electrical conductivity (σb) were recorded in different pits along one of the transects to calibrate the EMI measurements and to compare with the modeled electrical conductivity (σ) obtained by the joint inversion of multiconfiguration EMI measurements. Estimates of σ were then converted into the universal standard of soil salinity measurement (i.e., electrical conductivity of a saturated soil paste extract – ECe). Soil apparent electrical conductivity (ECa) was repeatedly measured with the CMD mini-Explorer to investigate the temperature stability of the new system at a fixed location, where the ambient air temperature increased from 26°C to 46°C. Results indicate that the new EMI system is very stable in high temperature environments, especially above 40°C, where most other approaches give unstable measurements. In addition, the distribution pattern of soil salinity is well estimated quantitatively by the joint inversion of multicomponent EMI measurements. The approach of joint inversion of EMI measurements allows for the quantitative mapping of the soil salinity distribution pattern and can be utilized for the management of soil salinity.