Summary of the Seminar Content
The seminar which I attended had a talk on the overview of hydrology and gravity, instrumentation, modelling and monitoring of artificial recharge, the monitoring of channel infiltration, and the future of hydro geophysics in general. Each of these and subtopics is described below
Hydro geophysics
Hydro geophysics is the measurement of the change of gravity to enable the monitoring of the soil moisture, the ground water flow and the infiltration parameters. A good number of geophysical methods are narrowed by the relationship between identified property such as electrical resistivity and the characteristic of interest such as moisture. Improving the resolution of measurements does not give better information. However, instrumentation is established, and the advancements in technology will lead to incremental improvements only.
Gravity
The gravity is regulated by the time and expense required for data collection for its analysis. The changes can be quantified in the water in distribution in space if the speed, precision and deplorability, is improved.
Figure 1: Gravity anomaly
Figure 2: Observed gravity
Airborne sensors
These gadgets are used extensively to get the information regarding the gravity. However, the gravity is very sensitive to the slope and as such the paths of the flights cannot be positioned or repeated precisely for applications on time-lapse systems. This limits the applications to space and terrestrial only in the future.
In summary, the gravity gives information concerning the spatial distribution of changes in storage, location of the wetting front and rate of infiltration, and the parameters of the hydrological model. Moreover, the data shows the SAVSARI recharge facility operation in a quasi-steady state with the water flowing outside or being removed from the facility boundaries. The modelling of 3-dimensional unsaturated zone of flow is difficult in spite of the simple forward modeling of gravity
Units
The unit of gravity is micro Gal which is equivalents to 1x 10-8 m/s2
The earth has 1x 10-8µGal
How Gravity and Hydrology works
Figure 3: How gravity and hydrology works
The Newton’s law of gravitation has the following relation
F=Gm1m2/r2
The vertical component is given by; g = mz/r3
Assuming that the density charge value, the mass is discretized, and the Newton’s law is applied to each element.
Implications of Newton’s Law
When the mass and the density change is known, the region of occurrence of can be identified, and the opposite is true, both of these cannot be done- no resolution of depth. Also, the volume of support is infinitely effective, and the distance at which the sensitivity drops to zero does not exist. This is because the gravimeter sensor senses over an increasingly wider area. The application of Newton’s laws in gravimetry analysis makes any kind of hydrological model to be easily calculated.
Instrumentation
The parameters of instrumentation are relativity, absolute and superconductivity.
Figure 4: Instrumentation
Artificial Monitoring of Recharge
The infiltration flux increase with time for recharge basins while the change in gravity matches the infiltration cycles so closely. When the water level changes, it matches with the total infiltration. There will be little or no accumulation of any storage in steady state conditions. The A-10 and continuous records match perfectly with the unavoidable data gaps. This results in the noise of high-frequency in water levels with a large change in gravity.
Figure 5: Artificial recharge monitoring
In this case, the work of gravity was motivated by the difficult access for installation of the piezometer. This is used to provide a specific yield so that the changes in the water levels can be converted to changes in storage.
Figure 6: Pulse flow of Colorado River
Artificial Recharge Modelling
The levels of ground water depend on the processes included in the simulated model. The simulated sensitivity of gravity is near the parts of the models, but distant basins and wells for pumping have only a little effect. This makes the gravity an effective feature for model superposition and calibration.
Figure 7: Artificial recharge modelling
Importance of hydro geophysics in Career development
Hydro geophysics involves a lot of cultivation into new ways of solving engineering and social problems. Therefore, the Newton’s law of motion, gravimentry, instrumentation and other parameters learnt in the seminar has applications in the real life. They can be in engineering design, communication, professionalism, etc. We shall reflect on two areas of the seminar content in the career development.
Engineering design applications
The knowledge gravimetry relates with engineering design prospect. For example in the design of the structures and buildings, on need to have some sound knowledge of soil mechanics and hydrology. Hydrology deals with water studies; precipitation on rain gauges, ground water, the moisture content of the soil, and other water parameters. Hydro-geophysics involves the use of methods that are geophysical in nature to parameterize the surface features that determines the hydro-geological features and checking the activities that are that are relevant to water and soil processes. The hydro-geophysical methods may allow the large-scale characterization of aquifers that were previously obtained from the conventional hydrogeological techniques. Moreover, the appropriate methods of time-lapse can provide useful idea in the complex subsurface processes that aids in the development of and restoration of ground water strategies. The research on hydrology has facilitated the development of sophisticated tools that account for model uncertainty with respect to the inadequate knowledge about the subsurface hydraulic property distribution. The stochastic techniques have incredible growth of both surface and subsurface hydrology. The data that is acquired from geophysics is useful in structural characterization, fluid dynamics, presence and contaminants motion. The Geophysics have used for a long time to support hydrogeological studies but mainly for delineation of lithological boundaries. An example is the geometrical characterization of aquifers (Khalil and Gamal, 2)
Professionalism
The science of hydrology and geophysics is one’s specialization. An individual who concentrates in this particular field will be able to do vast research on several items pertaining the subject. As part his or her career, one will use the techniques and some equations that were considered in the previous seminar attended. The same will be valuable tools for further research on the area by the professional individual.
The hydro-geophysical methods have been concentrated in most areas of applications in saturated, unsaturated zones and soils. These areas need deep interests in the hydrological sciences despite the many problems associated with space and time. The hydrological science has made advancement towards the understanding of more complex systems and critical hydrosphere interfaces in particular. The understanding of the interaction between the subsurface and the surface water bodies are gateways to good management of water resources (Khalil and Gamal, 2)
The usual techniques for doing hydro-geophysical research are the use of GPR and ERT, but novel techniques have grown in the recent years. The spectral induced polarization (SIP) in an expanded method of induced polarization and uses measurements of multi-frequencies. The SIP and IP methods provide important information on how signals are affected along the grain boundary. This technology uses the idea of the potential differences of electricity in the ground (Khalil and Gamal,
Work Cited
Khalil, Mohamed H., and Mohamed A. Gamal. "Hydro/Engineering Geophysical Parameters and Design Response Spectrum for Sustainable Development in Ras Muhammed National Park, Sinai". Pure and Applied Geophysics (2016): n. pag. Web.
