Hydrology in Civil Engineering

HYROLOGY IN CIVIL ENGINEERING
By Name
Course
Instructor
Institution
Location
Date

Abstract
The main aim of this study-work is to discuss how water-cycle has impacted on the environment,
various methods for measuring flow-rate and usage as well the separation of base-flow from
hydrograph. Water is a basic component of human life and a better part of the earth's surface is
occupied by water. Therefore, stream-flow hydrograph analysis is necessary to help in the
understanding of base flow can be separated from the hydrograph stream's discharge.
Introduction
From previous research and findings, it is believed that the earth surface is covered by water
which constitutes about 70%. The hydrological cycle is a process that involves continuous-
circulation of water on earth surface. The formation of water includes evaporation, transpiration,
condensation, precipitation, and run-off. Evaporation is the process by which the heated water
surface is lost into the atmosphere (Marsalek et al., 2014) This water mass lost turns into gaseous
state and condenses (process of condensation) back in liquid form, that raindrops (process of
precipitation) and eventually to running floods (surface run-off).
Impact of water-cycle to the environment
Human-population has been rapidly increasing and this has exerted a lot of pressure on the
earth's surface resources. Further, the need for many countries across the world to be heavily
industrialized also significantly affects the environment, for example, poor methods of disposing
of industrial wastes have led to water pollution.
There has been a lot of debate about the changing climatic situation or patterns caused by the
emission of greenhouse gases into the atmosphere as well as deforestation acts which have
facilitated the problem of desertification. This has led to high temperatures hence global

warming and land encroachment leaving no forest cover that acts as water catchment areas. In
general, these issues have a reciprocating effect on the hydrological water cycle (Jiang,
Hendrickson and VanBriesen, 2014).
The following factors have a great influence on water-quality thereby impacting on the
environment.
Pollution by chemicals
Even though there is a growing need for industries across the world, there still exist a number of
challenges created by these industries. For example, chemical industries have widely contributed
to the contamination of water sources. Fertilizer manufacturing-plants quite often release harmful
waste gases like Nitrogen and Phosphorous into the atmosphere. When these gases get to the
atmosphere, they form chemical compounds such as Nitrates and Phosphates (Mills et al., 2014).
The nitrates formed increases the process of eutrophication which in turn facilitates the growth of
algae and macrophytes thereby contaminating water sources quality. This is a dangerous health-
hazard for the human population since it results in cancer cases. Phosphates, on the other hand,
are harmful to the growth of aquatic-plants which is as an atmospheric-nitrogen fixer.
Phosphates, therefore, become a limiting-agent to the growth of algae and macrophytes.
Biological-water pollution
Bacteria are single-celled micro-organisms that are considered to be dangerous water pollutants.
Because of their tiny sizes, they can transmit several diseases through contaminated underground
water-systems. The main problem with bacterial-pollution is should biological-hazard occur in a
particular region, then through water circulation processes, it is likely to be transmitted to many
kilometers spreading to several regions across the world. It is therefore important to note that

sewerage-systems that carry human wastes and piped-water should be constructed far away from
a water source to avoid this kind of contamination (Qiao et al., 2015).
Chemical-Weathering
Weathering refers to the process by which chemical and physical processes breaks-down the
rock-structures that are found on the earth surface. Weathering occurs when there is direct
exposure of the earth's rock-material to water and air. Disintegration normally occurs at the
submicroscopic surface due to the weathering processes hence making pores of exposed rock-
materials and the fractured surfaces to allow chemical-weathering to take place (Gericke and
Smithers, 2014). This process of chemical weathering is accelerated by increased concentration
of chemicals that are subjected to the earth's atmosphere.
The rate of chemical weathering is influenced by three key elements; temperature, amount of the
earth's surface area and the available water sources or natural-acid. This is the reason why the
environment in the tropics does experience a high and acute level of weathering processes.
During these chemical processes, water is used as a solvent material that will make several
chemicals dissolve to form chemical compounds.
Methods of measuring flow rates in natural watercourses
Measurement of flow-rates in natural watercourses is a very important exercise that should be
carried to determine the quantity of earth surface-outflow of a given basin, its temporary
variation and the features of outflow. The measurement should be simple, reliable and accurate.
For this to work out, the hydrometric-station should be well equipped with the necessary
facilities and adequate staff. Below are some of the methods used to measure the flow-rates of
natural watercourses