Groundwater Hydrology

The Meteoric Isotope Line

Harmon Craig published (1961a) a dD and d18O diagram, based on about 400 water samples of rivers, lakes, and precipitation from various countries (Fig. 9.4). An impressive lining of the data along the best-fit line of has been obtained. Outside this line plot data from East African lakes that undergo significant isotopic fractionation due to intensive evaporation losses. Fig. 9.4 Isotopic data of about 400 samples of rivers, lakes, and precipitation from various parts of the world. The best-fit...

Discharge Measurements and Their Interpretative Value

Discharge is the measure of the amount (volume) of water emerging from a spring, or pumped from a well, per unit time. A wide array of discharge units exist in the literature, but cubic meters per hour (m3 h) is recommended. Discharge may, in certain cases, be measured in the field with the aid of a container of known volume and a stopwatch. The discharge is calculated from the volume (number of times a vessel is filled) and the time involved. Occasionally spring water flows from several...

Altitude Effect

Altitude Verse Phenomenon

The altitude effect is seen in Fig. 9.15. The d18O values in Swiss precipitation are lighter with higher altitudes. The gradient, or altitude effect, is 0.26 d180 100m altitude. The altitude effect is observed in this case to be the same in the precipitation and in the derived surface and groundwaters. This effect is not masked by the seasonal temperature effect (Fig. 9.10). The altitude effect has to be established in each study area. Leontiadis et al. (1983) reported a value of 0.44 100m for...

Monitoring Leachate of a Sanitary Landfill

Samitary Land Fills

Fritz et al. (1976) studied possible movement of leachate from a sanitary landfill in Frankfurt am Main, Germany. In a preliminary search for suitable tracers it was found that the leachate leaving the waste disposal site was enriched in deuterium and 18O (possibly due to evaporation). The leachate was enriched by 1.5 2.0 of d18O, whereas the analytical resolution was + 0.1 . The site operated from 1925-1968, and about 1.8 x 107m3 of garbage were deposited there. The underlying phreatic...

The Logarithmic Concentration Axis

The set of data in Table 6.4 was generated so that the concentration of dissolved ions increases from data set 1 to set 5, but the relative abundance of the ions is preserved (check it, for example, by comparing the Mg Ca ratio in data sets 1-5, Table 6.4). This imitates dilution of a saline water by different amounts of a fresh (ideally, distilled) water, a common occurrence in nature. The data of Table 6.4 have been plotted once with a linear concentration axis (Fig. 6.2) and once with a...

Isotopic Fractionation During Evaporation and Some Hydrological Applications

Example Evaporation Natural Cases

Evaporation is a physical process in which energy-loaded water molecules move from the water phase into the vapor phase. Isotopically light water molecules evaporate more efficiently than the heavy ones. As a result, an isotopic fractionation occurs at partial evaporation of water the vapor is enriched in light water molecules, reflected in relatively negative dD and d18O values. In contrast, the residual water phase becomes relatively enriched in the heavy isotopes, reflected in more positive...

Bunter Sandstone Aquifer Eastern England

The Bunter sandstone aquifer has been studied over an area of 2000 km2 in eastern England (Fig. 11.18). A large body of data has been published by Andrews and Lee (1979) and Bath et al. (1979). The regional geology, shown in Fig. 11.19, reveals a sequence of formations from the Permian in the west to the Jurassic in the east, the strata dipping eastward. A more detailed geology of the study area, with sampled well locations, is given in Fig. 11.20, and a cross-section is given in Fig. 11.21....

Karstic Systems Paths of Preferred Flow

Hard calcareous rocks, that is, limestone and dolomite, develop specific features noticeable on the land surface dissolution fissures, cavities, caves, and sinkholes in which runoff water disappears. On the slopes of such terrains occur springs with high discharges that often undergo a marked seasonal cycle. In such terrains intake of recharge water and underground flow are in open conduits (sections 2.1 and 2.2). A classical area of such conduit-controlled water systems has been described in...

Chemical and Physical Measurements During Pumping Tests

The common interpretation of pumping test data is based on the assumption that only one aquifer is pumped and tested. However, the intensive pumping during the test causes a significant local pressure drop in the pumped aquifer that may cause water from an adjacent aquifer to breach in (Fig. 4.14). If the pumping test is done in a phreatic aquifer, water of a lower confined aquifer may flow in. Similarly, in pumping tests in confined aquifers, an overlying phreatic aquifer may be drawn in. The...

Manmade Tritium Inputs

Nuclear bomb tests, which began in 1952 in the northern hemisphere, added large amounts of tritium to the atmosphere. They reached a peak in 1963, with up to 10,000 TU in a single monthly rain in the United States. An international treaty stopped surface nuclear bomb tests in 1963, and tritium concentrations in precipitation decreased steadily. Since nuclear testing began, tritium (and dD and d18O) has been measured in a worldwide net of stations (Fig. 10.2), coordinated by the International...

Key Topics for Museums Exhibitions and Teaching Activities

Let us discuss the education aspect of the global water cycle in two steps first the extended list of potential topics, and then how these topics can be integrated into water and man science museums (section 18.4.2), local exhibitions (section 18.4.3), teaching at schools (section 18.4.4), and teaching at universities (section 14.4.5). The topics are by and large elucidated in the present book. List of key topics of the global water cycle. Water the unique fluid Water the magic liquid of our...

Importance of Historical Data

The data collected during the drilling of the Amiaz 1 well (section 7.2 and Fig. 7.1) were put aside once the drill entered saline water and the well was abandoned. Several years later a water source of low output but good quality was needed in the area on that occasion all historical data were scanned and studied. The existence of the required water body was spotted from the historical data, at no extra cost. A study of groundwater systems along a transect through the Judean Mountains, central...

Answers To Exercise Questions

Answer 1.1 It seems easy to grasp that along the seacoast all rivers flow into the sea. The observation that all rivers run into the sea describes runoff. Water flows down along the topographic relief, and the sea is the terminal base of drainage. Answer 1.2 The law of mass conservation. When we pour water into a vessel, the level of the water rises not so in the case of the sea. So, there must be an outlet of water from the ocean. Answer 1.3 Two segments of the water cycle were concealed the...

Water Table Measurements

The depth of the water table in a well is measured relative to an agreed-upon mark at the top, for example, the edge of the casing. This reference point should be clearly marked to ensure reproducibility of the measurements. The depth of the water table is obtained in meters below the top of the well or, more meaningfully, in meters below the surface, as shown in Fig. 4.1. AC is the depth of the water table below the reference mark at the edge of the well casing (or any other selected mark)....