UNIVERSIDAD SANTO TOMAS VILLAVICENCIO

TALLER DE RECURSOS HIDRAULICOS

PRESENTADO POR

QUINTO SEMESTRE

INGENIERIA AMBIENTAL

PRESENTADO A

ING. IVAN HERNANDEZ

VILLAVICENCIO- META

Chapter 1

Properties of fluids

1.1 Introduction

What is the definition of fluid?

RTA: Fluid mechanics is the science that studies the effect of forces applied to the fluid. A fluid is any substance that can flow, as well as liquid gases[1]

Specify the forms of matter that are embraced by the term fluid

RTA:a) Viscosity. Viscosity is the measure of the internal resistance of a fluid to displace or moverse.Tanto the air and water to flow easily though, have some degree of difficulty flow. When molecules of a moving fluid, internal forces tend to counteract the force applied to the fluid to put in motion they are presented. [2]

b) Surface tensionThe surface tension causes the free surface of a liquid behaves like a thin very weak and thin elastic membrane that can stretch upon application of a small force and may even romperse.La surface tension is a measure of the magnitude of the forces to They are acting on the inner surface of a liquid. Each liquid has a different surface tension value, which depends on the intensity of the forces of cohesion. [2]

c) Cohesion

Cohesion is the force of attraction that holds molecules of the same substance. Cohesion is higher in solids than in liquids and these were more than in gases. But on the molecules of the liquid does not act only cohesion forces; also they act repulsive forces prevent them placed too close to each other and also the gravity acting on them, forcing the upper layers of the liquid to slide on the lower, reaching the same level on the surface. [2]

c) accession or adhesion.It is the force of attraction occurs between the molecules of two different substances are contacted; usually a liquid to a solid. Generally liquids, stick to solid bodies. When the sticking phenomenon occurs it means that the bond strength between molecules of the same substance is greater than the cohesive force experienced with a different substance, with which they contact. Such is the case of water that adheres to the glass, paint adhering to a wall, the oil to adhere to paper, ink or a notebook. Cohesion and adhesion. By bringing together a liquid with a solid result that we in the contact surface there are two forces opposite trend. [2]

d) Capillary.The capillary phenomenon, is the ascent or descent of a liquid

within a small diameter tube called capillary. [2]

f) Density.The density of a substance is defined as the mass contained in unit volume. the mass is a measure of the amount of material containing a substance. g) Relative DensityThe relative density of a body is the result of dividing the density of said body between the density of water. [2]

h) Specific Gravity The specific gravity of a substance is defined as the weight of substance per unit volume. [2]

i) Pressure When you sleep on a mattress in it deformation occurs, but is higher if you stand on it. Although your weight does not change by changing the position of the body is greater deformation in the mattress because the contact area decreases. [2]With it, called atmospheric pressure. [2]

k) Hydrostatic Pressure

Hydrostatic pressure is that pressure of a liquid due to its weight, especially body that is immersed therein. [2]

1.3 Mass density and specific weight

State the definition of mass density (or just density) and its formula.

RTA:

The density of a substance is the ratio between the mass and volume:

The mass and volume are extensive or general properties of matter, ie are common to all material bodies and also depend on the amount or extent of the body. [3]

State the definition of specific weight and its formula.

RTA:

The specific gravity of a fluid is calculated as the weight of a unit volume (or density per g). In the international system it is measured in Newton / cubic meter. [4]

1.4 Relative density

State the definition of relative density and its formula (for water)

RTA:

The relative density is a comparison of the density of a substance to the density of another that is taken as reference. The relative density has no units, since it is defined as the ratio of two densities. Usually the density is used as the water is

constant, which as we know in m3 equals 1,000. [4]

1.5 Viscosity of fluids

- State the definition of viscosity.

RTA: Viscosity.

Viscosity is the measure of the internal resistance of a fluid to displace or moverse.Tanto the air and water to flow easily though, have some degree of difficulty flow. When molecules of a moving fluid, internal forces tend to counteract the force applied to the fluid to put in motion they are presented. [2]

- Specify the formula of Newton’s law of viscosity.

RTA:

Newton's law of viscosity.

Considering the flow between two plates. After a certain time profile reaches its final steady state. Once this state is reached movement must apply a constant force Fx to retain the movement of the bottom sheet. This force clearly depends on the speed V, of the nature of the fluid, the distance between the plates (b) and the contact area S thereof with the liquid. For this special case it is given by: [6]

That is, the force per unit area is proportional to the speed decrease with distance z. The proportionality coefficient μ is called fluid viscosity. Using deltas can be written: [6]

Where the slope of the curve vx against z is Δvx / Az. Taking the limit as z approaches 0 approximates the true gradient at z, which is given by the partial derivative ∂vx / ∂z. The resulting basic equation for unidirectional transport of momentum is unstable: [6]

Called Newton's law of viscosity in one dimension. τzx is the shear stress applied in the x direction on the surface of a fluid located at a distance z, for the fluid in the region where z is lower. Fluids that obey the above equation are called Newtonian. According to the considerations made, τzx can also be interpreted as the density of viscous flow amount of movement x (flux density is flow rate per unit area, or which are units of momentum per unit time and unit area) in the direction z [6]

State the definition of Kinematic viscosity.

Rta:

Kinematic viscosity

As a convention, the kinematic viscosity is defined as the ratio of the dynamic viscosity of a fluid and its density. Because the dynamic viscosity and density are properties of the fluid, the kinematic viscosity is too. [7]

- What are the approximate Dynamic and Kinematic viscosity of water? (include the formula).

RTA.

Units dynamic viscosity and the kinematic viscosity

In the international system (SI) unit of dynamic viscosity is the Pascal second (Pa.s) or even Newton second per square meter (Ns / m2), or kilogram meter per second (kg / ms). [7]

The corresponding unit in CGS system is Poise and has dimensions of Dina second per square centimeter or grams per square centimeter. The centipoise (cP), 10-2 poise, is most often used to express the dynamic viscosity because most have low viscosity fluid unit. [7]

In the international system (SI), the unit of kinematic viscosity is the square meter per second (m2 / s). The CGS unit is the corresponding Stoke (St), with dimensions of square centimeter per second and Centistoke (cSt) 10-2 Stokes, which is the most commonly used submultiple.[7]

ν = μ / ρ (m2 / s)

1.6. Compressibility and elasticity of fluids

- What is it required for all fluids to be compressible?

Rta.

Compressibility refers to change in volume of a substance is subject to a

change of pressure on it. What it measures this phenomenon is called bulk modulus of elasticity, or simply bulk modulus E. [8]

E= −∆ P∆V /V

∆ P- Variation less initial pressure final pressure

∆V - Volume change experienced by the substance

V- Initial volume of the substance before applying pressure

- According to the formula above, what does the negative sign indicate?

Rta

The negative sign in the above formula represents the elasticity of the fluid

1.7. Vapour pressure of liquids

- When does a liquid in a closed container reach a stage of equilibrium?

Rta

If a closed vessel, which was previously made empty, partially filled with a liquid substance A, it is partially evaporate (if sufficient for the process is not total amount), so as to reach finally, a steady state in which the pressure in the container is the vapor pressure of the substance at the temperature considered [9]

1.8. Surface tension and capability

-What are the properties that liquids possess? And due to what/ or why?

Rta

Liquids are deformable systems constituted by an infinite number of isolated points infinitesimal materials. It is continuous systems where there are no "empty spaces" within the mass. From the point of view of mechanics include the following fundamental properties of liquids: [9]

Isotropy: are known as isotropic substances whose properties are identical in either direction. [9]

Mobility: Lack of proper form. Ability to take any form, the vessel that contains them. [9]

Viscosity: Also called dynamic viscosity (μ) of a fluid is the resistance that it opposes deformation, or in other words, to the sheets of fluid slide between its immediate. [9]

- State the definition of Surface tension.

Rta

The cohesive forces between the molecules of a liquid, are responsible for the phenomenon known as surface tension. Surface molecules have no other equal on all sides, and thus more strongly cohere with those associated directly on the surface. This forms a surface film, which makes it difficult to move an object across the surface, which when fully submerged. The surface tension is usually measured in dynes / cm., The force required (in dynes) to break a film of 1 cm. of length. It can be set by an equivalent surface energy in ergs per square centimeter [7]

Chapter 8

Steady Flow in Open Channels

8.1 Introduction

- What are the characteristics of an open channel?

Rta

The open channel flow should have a free surface, while the pipe flow does not, because in this case the water should completely fill the duct. A free surface is subjected to atmospheric pressure. the free surface can change over time and space, and also by the fact that the depth of the flow stream and the slopes of the channel bottom and free surface are independent [10]

- Does a sewer flow in the same way than a river?

Rta

Sewer, flowing partially full, is a covered channel with a comparatively short length installed to drain water through road embankments or railways. [10]

8.2 Uniform flow resistance

- Which equations apply for non-circular sections?

Rta

The equations from non-circular section according to featheerstone “are the equation of darcy-weisbach and colebrook White [11]

Equations Darcy-weisbach

h fl

Sf= So= γv 2

8g R

Colebrok White:

: 1√

-2 log [k

14.8 .R +

2.51v4 r v√❑ ]

8.3 Channels of composite roughness

- What was the assumption from Horton and Einstein about sub-area?

Rta

According to featheerstone “The wáter área is divided into N parts having wetted perimeters P1,P2… with asossiated roughness coefficients n1, n2… nN. Horton and Einstein asumed that each sub área has a velocity equal to the mean velocity: [11]

8.4 Channels of compound section

What would be an example for a compound section?

Rta

The example can be a cannel with flood plains. Acording to featheerstone “The rougnhness of the side channels and the method of analysis is to consider the total discharge to be the sum of component discharge computed by the mannin equation” [11]

- According to the research data from the flood channel facility at Wallingford, what has it been shown?

In accordance with featheerstone and Nalluri “shown that the discrepancy between the conventional calculations and the measure flow is dependent on flood flow levels. He formulated aprropiate corrections factor for each region of flow; a detailed exposure of the analysis of the research is beyond the scope of the book” [11]

8.5 Channel desing

- What is it involved in the design of open channels

Rta

In accordance with featheerstone and Nalluri “the selection of suitable sectional dimension such that the maximum discharge will be conveyed withi the section, The bed slipe is sometimes constrained by the topography of the land which the chanell is to be constructed” [11]

8.5.2.1 Critical tractive force theory

- State the definition of tractive force.

Rta

In accordance with featheerstone and Nalluri “he force exerted by the water on the wetted area of a channel is called the tractive forcé [11]

8.5.2.2 Maximun permissible mean velocity concept

- What was published by Fortier and Scobey in 1929?

Rta

In accordance with featheerstone and Nalluri “Fortier and Scobey published the values of or well-seasoned channels of small bed slope and depths below 1 m in the next table” [11]

8.6 Uniform flow in part-full circular pipes

- How are the storm sewers designed?

Rta

In accordance with Featheerstones and Nelluri “Storm sewers are usually designed to sufficient capacity, but this dependt with the material of the sewers, they do not run full when conveying the computing surfacerun off resulting from a storm of a specified average return period” [11]

- State the use of circular pipes.

Rta

According to Featherstone and Nelluri “Circular pipes are widely used for underground storm sewers and waste-water sewers” [11]

8.7 Steady, rapidly varied channel flow energy prínciples

- What does the computation of non-uniform Surface profiles require?

Rta

The computation of non-uniforme surface profiles according to featheerstone and Nelluri “is caused by changes of channel section, etc, requires the application of energy and momentum principles.

The energy per unit weight of liquid at a section of a channel above some horizontal datum is:

[11]

8.8 The momentum equation and the hydraulic jump

- State the definition of hydraulic jump.

Rta

The hydraulic jump In accordance with featheerstone and Nalluri “is stationary surge and occurs in the transition from a supercritical to subcritical flow, a smooth transition is not possible” [11]

- What is the name of the depth at which the hydraulic jump starts?

Rta

Downstream depth

8.9 Steady, gradually varied open channel flow

What is the result when motivating and drag forces are not balanced?

Rta

Steady gradually varied open channel flow, in accordance with Featheerstone

and Nelluri”this condition occur when the motivating and drag forces are not balanced with the result that the depth varies gradually along the length of the channel” [11]

8.10 Computations of gradually varied flow

What method can be used to solve the gradually varied flow equation?

Rta

The graphical integration method is widely applicable. However, with the advent of electronic calculators and specially digital computers it is often more convenient to use numerical method; such methods are applicable to general cases of non-prismatic channels of varying slope

8.11 The direct step method

State the meaning of the direct step method.

Rta

The direct step method In accordance with featheerstone and Nalluri “is a simple method applicable to prismatic channels. As In the graphical integration method depths of flow are specified and the distances between successive depths calculated” [11]

8.12 The standard step method

When can the standard step method be applied?

Rta

The standard step method In accordance with featheerstone and Nalluri “is applicable to non-prismatic channels and therefore to natural rivers. The station positions are predetermined and the objective is to calculate the surface elevations, and hence the depths, at the station. A trail and eror method is employed” [11]

8.13 Canal delivery problems

What are the characteristics of the reservoir-canal-reservoir?

Rta

When a channel is connected to two reservoirs its discharge capacity depends upon inlet (upstream) and outlet (downstream) conditions imposed by the waters levels in the reservoir. The reservoir- canal-reservoir interaction In accordance with featheerstone and Nalluri “depends upon the channel characteristics such as its boundary roughness, slope. lenght between reservoirs and the state of water levels in the reservoirs” [11]

8.14 Culvert flow

- Where can culverts be located?

Rta

Hightway cross-drainage is normally provided with culverts, bridges and dips.

culverts are submerged structures buried under a high level embankment.

What are the characteristics of the hydraulic design of the culvert?

Rta

the hydraulic design of the culvert In accordance with featheerstone and Nalluri “is based upon the characteristics of the barrel flow ( free surface flow, orifice flow or pipe flow), Conditions which depend on its leght, roughness, gradient and upstream and dowstream water levels” [11]

8.15 Spatially varied flow in open channels

How is the SVF represented?

Rta

Spatially varied flow (svf) In accordance with featheerstone and Nalluri “is represented by the discharge variation along the lenght of the channel due to lateral inflow (slide spillway channel) or outflow [11]

Chapter 13

Unsteady Flow in Channels

13.1 Introduction

State several examples of unsteady cannel flows.

Rta: There are two types of unsteady flow: non permante gradually varied flow and no permanent rapidly varied flow. Some common examples of gradually varied unsteady flow waves are growing and due to the slow operation of control structures, such as gates and sliding gates in locks. Examples of rapidly varied unsteady flow surges are difenrestes classes, caused by rapid operation of control structures. [12]

Explain what surges are.

Rta: In the first type the curvature of the waveform is gentle and the change in depth is gradual. Omponent vertical acceleration of water particles is negligible compared to the total aceleraion, while the effect of the friction of the channel often is significant and should be considered for an accurate analysis.

In the second type the curvature of the waveform is very large, so that the profile surface may become virtually discontinued. The vertical component of acceleration, therefore plays an important role in the phenomenon, while the effect of friction in the channel is negligible compared with the dynamic flow effect. [12]

From a stationary observer’s perspective, what is the velocity of a wáter wave? (formula)

Fₒ = FF Vs±VoVs∓Vf

fo = frequency perceived by the observer

ff = actual frequency emitted by the source

v = velocity of water

vo = velocity of the observer (also used as speed vr or receptor)

VF = velocity of the source (also used as looks or speed of the issuer)

We must focus attention on the + signs (plus) and - (minus) of the equation. Note that appears in the numerator ± (plus or minus) and the denominator is reversed (less more). This placement of signs is very important as it use one or the other depends on whether the observer is moving towards or away from the sound emitting source. [12]

Chapter 14

14.4.1.3 Grade-Ranga raju´s formula

Garde and Ranga Raju (1966) analyzed data from flumes, Canals and natural streams, and a graphical relationship (Figure 14.2) between the parameters K1V/√ (∆ gR ) vs. K2(R/d)1/3S/∆, where K1

and k2 are functions of sediment size (see Figure 14.3), was proposed. Figures 14.2 and 14.3 facilitate the calculations of discharge in alluvial channels.In the case of rectangular channels (bed width B) with smooth sides Einstein suggested the following equation for the hydraulic radius of the bed:

Rb=¿

Where the hydraulic radius corresponding to the walls Rw is computed from the Manning equation assuming it is applicable to the side walls and the bed independently. Vanoni and Brooks (1957) proposed for rough channels with smooth sides that

Rb=γbV

2

8gS

14.5 Velocity distributions in loose-boundary channels

Einstein´s equation in the form

u

U ¿´=5.75 log (30.2 yx

ks) [14.12]

Where u is the temporal mean velocity at a distance y from the boundary is applicable universally for smooth, transition and rough beds. The correction factor x is a function of k s/ δ ´(δ ´ sub-layer thickness given by 11.6v/U) given in Table 14.1

Equation 14.12 gives the mean velocity V as

V=5.75U ¿ log( 12.27 Rxks

¿)¿

For k s/δ ´ > 6.0, the boundary is fully rough and the Manning-Strickler equation could conveniently be used to calculate the mean velocity.

14.6

Sediment transport Characteristics

When flow characteristics (velocity, average shear stress, etc.) in an alluvial channel exceed the threshold condition for the bed material, the particles move in different modes along the flow direction. The mode of transport of the material depends on the sediment characteristics such as its size and shape, density ρ s and

movability parameter U ¿/W s, where W s is the fall velocity of the sediment particle.

Fall velocities are equally of importance in reservoir sedimentation and settling processes and may be expressed as W s=f (shape and density of sediment, number of particles falling, particle Reynolds number)

The fall velocity of a single spherical particle can be written as

W s=√ 43g∆ dCD

14. 7 Bed load transport

Several empirical equations from laboratory flume data have been proposed by many investigators with the basic assumptions that the sediment is homogeneous and no cohesive. The results differ appreciably and it is dangerous to transfer the information to outside the limits of the experiments. However, one can discern general trends of the transport rate by using several formulae (with some theoretical background). The following are the most commonly used equations

1. Shields equation :

Shields used the concept of excess shear responsible for the transport and presented a dimensionally homogeneous equation

2. Schoklitsch equation The bed load gb in kg/m.s is given by

Where qcr = 0.20 (∆ ¿5/3 d3/2/S7/6

It must be noted that equation is not dimensionally homogeneous and is valid only for q and qcr in m3/ms.

3. Kalinske equationFor Frd

2 ¿ 0.09 this can be written as

Qb/U*d = 10 (U*2/∆gd)2

Equation is dimensionally homogeneous and may not be good for high transport rates.

4. Meye – Peter and Muller formulaThe energy slope, S is split into two parts and only one part (uS¿ is considered to be responsible for transport (grain drag; the other is expended in the form drag). The factor u is dependent on the bed from (ripple factor) and is expressed as

Where C is the Chezy´s coefficient given by

In which k = d for Cgrain and k is a function of bed form (≈ dune height) for Cchannel.

5. Einstein´s equationIntroducing probability concepts of sediment movement Einstein developed an empirical relationship

14.8 Suspended load transportThe vertical (suspended) mass balance equation in a two

dimensional flow was first expressed by O´Brien as

Where c is the volumetric concentration of the sediment and ε s is the kinematic eddy viscosity (turbulence diffusion coefficient) in the presence of sediment, equal toβε, ε being the eddy viscosity for clear water. β is of the order of unity in the presence of fine sediment and decreases with increasing particle size. Combining equation 14.28 with the turbulent mixing theory (log law distribution of velocity) gives the solution for sediment concentration, c at a height, y in a channel as

Where ca is the reference concentration at a height a form the bed and X is Karman´s constant

14. 9 Total load transport

Total load includes both bed material load and wash load. Wash load is usually caused by land erosion and a useful criterion for its existence may be taken as the particle Froude number (=V/√ gd) around 20. Due to its small size fractions wash load moves in suspension and thus

can be estimated from the total suspended load provided the suspended bed material load is known.

14. 10 Regime channel design

Regime equations were developed using from stable channels in the Indian subcontinent, carrying moderate sediment loads of less than 500 ppm by weight.

2. Lacey´s approach

In which the silt factor, f, is given by:

Where d is in mm, P and R are in m and Q is un m3/s. The silt factor, f, is a function of its size, as indicated in Table 14.6. Lacey, combining equations, suggested the resistance equation:

3. Blench´s approach

Blench developed more rational formulae (using flume and Indian sub-continent data), taking into account the effects of bank cohesiveness on channel geometry and sediment load.

4. Simon. Albertson’s method

Regime channel data form the USA, Pubjab and Sind (Indian subcontinent) were analyzed by Simons and Albertson; their modified regime equations have a wider applicability.

5. Non-scouring erodible boundary channel design

This method approaches the criterion that the bed material (coarse) does not move when the channel carries either clear water or water with fine silt in suspension (not depositing). The principle of design is to achieve a cross section in which the boundary material is on the verge of motion (initiation criterion). The method utilizes the information on boundary shear distribution and the Shields initiation criterion (both on bed and banks) and establishes either permissible depth or slope (given one or the other).

6. Design of stable erodible boundary channel

Six channel/sediment parameters: Q, Qs, V, B, y0 and S.

14. 11 Regid-bed channels with sediment transport

Novak and Nalluri suggested for initiation of no cohesive coarser sediment (bed load):

The limit-deposition criterion in the case of rectangular channels is given by:

Where Cv is the limiting sediment concentration by volume that can be transported with a velocity Vs (self-cleansing). The overall friction factor γ s is given by:

Where γ cthe channel´s is clear water friction factor given by Colebrook-White´s equation the equations will give (by iterative solution) the design velocity for the self-cleansing criterion in rigid boundary rectangular channels with bedload transportation.In the case of clean pipe channels, the limit-deposition criterion may be written as:

With the friction factor γ s given by

The limit-deposition criterion in the case of pipe channels with deposited flat beds of width b is given by

Where γ s is given by

Chapter 15Hydraulic Structures

15.1 Introduction

Hydraulic structures are engineering works necessary to achieve the development of water resources and control their destructive action. They work in most cases in combination with elements and mechanical equipment. They are

built for the benefit of man and the development of humanity.

One can say that the waterworks is a group of structures built in order to control the water, whatever their origin, use purposes or defense.

15.2 Spillways

It is a hydraulic structure to produce, free or controlled through, water surface runoff, being exclusively for the overflow drain and not to the measurement. There are various types according to the form and use made of them, sometimes controlled and sometimes as a safety measure in case of storms in dams.

15.2.1.1 Negative pressures and cavitation

Operating conditions:

• Upstream pressure:1.2 ÷ 1.4 bar• Pressure downstream:0.1 bars• Fluid speed:2.2 m / sec(Referred to the diameterNominal)

15.2.1.2 Gated Spillways

Allows the evacuation of water, either routinely or to control the water level of the reservoir.

Areas near the free surface of the reservoir water is usually discharged, as opposed to the discharge line, which allows controlled waters off the deep layers of the reservoir.

15.2.1.3 Offset spillways

The effective length of the landfill is calculated using the formula:

Donde L’ es la longitud libre total del aliviadero, N es el número de pilas, y Kp y Ke son los coeficientes de contracción de las pilas y los estribos. Where L' is the total free length of the spillway, N is the number of batteries, and Ke and Kp are the coefficients of contraction of batteries and stirrups.

15.2.1.4 Effective spillway length

- When the crest has pierce its length must be reduced to..? (Formula).

Not found

15.2.1.5 Self-aeration

- What does imply steep slope?

It is the degree of inclination of a straight line, the reason of change in and with regard to the change in x. (FacultadBayamon, s.f.)

If a straight line happens for two different points (x1, y1) and (x2, y2), then his earring (m) is given for:

15.3 Energy dissipators and downstream scour protection

- What is the most effective way of dissipating the high energy of the incoming water?

Ponds dampers

 Type impact: It is a buffer structure where dissipation occurs when the arrival stream collides with a vertically suspended deflector and the swirling currents due to the change of direction of the current after having collided with cushion. It is imperative that the structure is strong enough to withstand the thrust produced by the jet without slipping and endanger the dam. (María, s.f.)

Immersion pools: The energy is dissipated through the water shock and free falling vertically in a pond in the riverbed. Due to the great erosive power of water, you have to coat the channel and its walls with rocks or concrete so it is kind of like a diving pool. Anyway materials suffer much wear from constant shock which is owed to good maintenance. (María, s.f.)

- What is the common type to dissipate energy?

The most used method is to induce in the flow a great turbulence by means of sudden changes both in direction and in expansion, since it happens with the hydraulic bounce (hydraulic jump), which is very effective in the dissipation of energy and turns the supercritical flow into subcritic. (PALACIOS, s.f.)

Chapter 16

Environmental Hydraulics and Engineering Hydrology

16.1 Introduction

- In your own words, explain the natural hydrological cycle.

Is a conceptual model that describes the storage and movement of water between the biosphere, atmosphere, lithosphere, and the hydrosphere. Water on our planet can be stored in any one of the following major reservoirs: atmosphere, oceans, lakes, rivers, soils, glaciers, snowfields, and groundwater. Water moves from one reservoir to another by way of processes like evaporation, condensation, precipitation, deposition, runoff, infiltration, sublimation, transpiration, melting, and groundwater flow

-How is water impounded in the environment?

It is confiscated by the moors, rivers, ponds, reservoirs, ice caps, groundwater and marine.

16.2 Analysis of gauge driver flow data

- When/where river discharges are required, what is the preferable way to work that out?

Separate recycling things, then calculate waste per day. Next process the waste to reduce it contamination according to national standards.

For design purposes concerning gauged catchments, what type of values may be analysed?

Runoff resulting from any rain, depends on the distribution in time and space thereof. If the rainfall is concentrated in the lower part of the basin, will produce higher flows than those they would have

if it took place in the upper part, where the regulatory effect of the flow, and the delay in concentration, manifested in a decrease the maximum discharge rate. (UNESCO, s.f.)

General weather conditions exist that influence, although in an indirect manner in the runoff, such as temperature, wind speed, relative humidity, barometric pressure, etc. (UNESCO, s.f.)

16.3 River Thames discharge data

- According to the text, what are hydrological day and water year?

The United Nations General Assembly adopted on 22 December 1993 resolution A / RES / 47/193 by which 22 March of each year was declared World Water Day, to be held since 1993, in accordance with the recommendations of the United Nations Conference on Environment and Development contained in chapter 18 (Fresh Water Resources) of Agenda 21. The different States are invited to devote this day, within the national context, the concrete activities such as the promotion of public awareness through the production and diffusion of documentaries and the organization of conferences, round tables, seminars and expositions related to the conservation and development of water resources as well as the implementation the recommendations of Agenda 21. (UNESCO, s.f.)

-Are the mean daily value and instantaneous maximum value different from each other?

The principal difference between daily and maximum, it’s that the maximum value it’s the highest value reached in the

investigation, while the daily value is an average by all the data of the day.

16.4 Flood alleviation, sustainability and environmental channels.

- Which are the main components of constructed works to alleviate the effects of flooding?

The systems of prevention are based on dikes, specks, metallic barriers, regulatory reservoirs and improvement of the capacity of outlet of the fluvial riverbeds.

-Which is one of the main components of sustainable urban drainage systems?

Sustainable Urban Drainage Systems can be considered as those elements involved in the drainage of cities and reduce the current flow across the surface of it, they get also significantly reduce the amount of contaminants carried by the runoff water. (Abellan, s.f.)

16.5 Project appraisal

- What method is it used to express the present values of costs and benefits?

The preferred method is cost-effective in the evaluation. Some believe that our techniques tend to underestimate the benefits of the projects. Others object that sometimes exaggerated estimates of the benefits are involved to meet the requirement of certain lobbies. (CATIE)

- How are all costs expressed? Explain how positive benefits and undesirable costs are reflected respectively.

PRODUCTIVITY INDICATORS

Degree of operating leverage: The degree of operating leverage, GAO, measures the impact of fixed costs on operating profit

to an increase in sales caused by investments in fixed assets (technology). (Váquiro, s.f.)

Opportunity cost: In absolute terms is the difference between the budgeted results of an investment and the results given. In relative terms is the percentage that has not received budgeted on results. (Váquiro, s.f.)

Breakeven: The point where operating income is equal to operating costs. In other words, it is the impasse where there is no income or operating loss. (Váquiro,s.f.)

Asset Rotation: Analyzes times become assets sales or operating income. (Váquiro, s.f.)

PERFORMANCE INDICATORS

Net profit margin: The ratio between net income and total sales (operating revenues). It is the first source of profitability in business and it depends on the return on assets and return on equity.

Gross margin: The ratio between gross profit and total sales (operating income) is the percentage of operating revenue remains after the cost has been discounted sales. The higher this index greater the chance to cover operating expenses and the use of the funding organization. (Váquiro, s.f.)

Sustainable Growth: The result of the application of sales policies, financing, dividends and capitalization. In modern times the strategy which contributes to the competitiveness of SMEs is precisely the strategy of growth, which suggests that the increase of sales, assets and

equity of the company, is consistent with the growth in demand. (Váquiro, s.f.)

FINANCIAL EVALUATION OF INVESTMENT PROJECTS

Consumer Price Index - CPI: An indicator that measures the average percentage change in retail prices between two periods of time, of a set of goods and services that households acquire for consumption. The change in the price of a good or service is the weighted sum of the item price variation in the cities surveyed. (Váquiro, s.f.)

Payback period Investment (PRI): One of the methods in the short term may have the favoritism of some people when evaluating investments. For ease of calculation and application is considered an indicator that measures both the liquidity of the project as well as the relative risk can anticipate events in the short term. Consists of measuring the period of time required for the net cash flows of an investment recover their cost. (Váquiro, s.f.)

Net Present Value: The best known method when evaluating investment projects in the long term. As the basic objective is to maximize financial investment, this tool can determine if the investment may increase or decrease the value of SMEs. That change in the estimated value can be positive, negative or remain the same. If positive means that the value of the firm will have a value equivalent to the increase VPN. If negative means that the company will reduce its wealth in value yielding the VPN. If the result is zero VPN, the company will not change the amount of their value. (Váquiro, s.f.)

Example: Calculate the cumulative value of an investment of 5,000 UM for a year, under the following conditions:

Solution:

PV = 5,000; n = 1 ... 4; i = annual 0.15, 0.075 and 0.0375 quarterly semiannual With 15% annual interest:

[19] VFn = 5.000 (1 + 0.15) 1 = UM 5750.00 with semiannual interest of 7.5%:

[19] VFn = 5.000 (1 + 0.075) 2 = UM 5778.13 with 3.75% quarterly interest:

[19] VFn = 5.000 (1 + 0.0375) 4 = UM 5793.25

The results are not the same, because the capitalization of interest we do so with different frequencies while maintaining proportionality in the different rates of interest.

To achieve that, whatever the frequency of capitalization and the final value remains the same is necessary to change the formula for the equivalence of interest rates

BIBLIOGRAFÍA

[1] Definición de fluidos// dr. Juan pablo Torres- Papaqui// departamento de Astronomía Universidad de Guanajuato

[2] Universidad autónoma del Estado de Hidalgo[3] concurso de ciencia y mecánica// curso de materiales propiedades de densidad[4] física practica.com[5] proyecto de física,blogspot.com[6] universidad Nacional Abierta y a Distancia[7] clases de viscosidad// Alejandra Rodriguez// facultad de química y física[8] Mott, Robert L., Applied Fluid Mechanics, Prentic Hall, 2000, 5th Edition[9] open course ware // universidad de Sevilla[10] Chow, Ven Te. Open-channel hydraulics. Blackburn Press.2009. 680 p.[11] Featherstone, R. Civil engineering hydraulics. 1995. 3 edit.[12] Hidraulica de canales abiertos // Libro Ven Te Chow