finals Flashcards
(27 cards)
The vertical distance from the center line of the discharge to the water surface in the well when there is no pumping.
Static Water Level
The vertical distance from the center line of the discharge to the water surface in the well while pumping. During a pumping test, the pumping water level is the depth
of water surface when the amount of water withdrawn from the well and the amount of
replenishment of water to the well are equal.
Pumping Water Level
The difference between the static water level and the pumping water level.
Drawdown
The volume of water per unit time that could be safely pumped from the well,
as determined by a pumping test.
Yield of the Well
The volume of water per unit time discharged by the spring.
Yield of the Spring
this method consists of determining the time required to fill a
bucket with water. For more accurate results, the measurement is repeated several times, and the
average time of these trials is taken. Note that using a bigger container will improve the accuracy
of the measurement.
Volumetric Method
A weir is an overflow structure built across an open channel for
the purpose of measuring the rate of flow of water. Weirs may be rectangular, trapezoidal or
triangular in shape. The Triangular or V-Notch Weir is a flow measuring device particularly suited
for small flows. The V-Notch Weir often used in flow measurements is the 90° V-Notch.
V-notch Weir Method
The following describes the procedure for measuring flow from a horizontal pipe as
shown above. Two conditions must be met for this procedure to work:
The pipe must be **flowing full **
The pipe must be horizontal .
Flow from a Horizontal Blow-off Pipe
Measurement of Water Levels in Wells
- Measurement of Water Levels in Wells
- Wetted Tape Method
3.Splashing Method
This is the ideal set-up when the location of the water source is at a
considerably higher elevation than the area to be served. The operation cost of a gravity
system is very low, as it does not require energy cost.
Through gravity flow
Water is either (a) pumped to a distribution pipe network,
then to consumers, with excess water going to a storage tank, or (b) pumped to a storage tank
first, then water is distributed by gravity from the tank to the consumers. The maintenance
and operation cost of this system is higher than a gravity system.
Through pumping with storage
In this system, water is pumped directly from the source to the
distribution system to the consumers. Where capital cost for a reservoir is not affordable at
the initial stage of the water system, direct pumping to the distribution is usually resorted to.
Variable speed or variable frequency drive pumps are most ideal for direct pumping
operations, but the capital costs for such equipment are higher than for conventional water
pumps.
Through direct pumping
is a force applied perpendicular to a body that is in contact with a fluid ,
in this case, with water. () increases linearly with the depth of water. For water at rest,
the variation of pressure over depth is linear.
Pressure
Shear stress is developed between the water and the pipe wall when water is
flowing. The shear stress is the result of friction, and is dependent on the flow rate, the roughness of the pipe, and the length and diameter of the pipe.
Head Loss
water in a pressurized pipe possesses **three form of energy **
Hydraulic Grade Line (HGL)
Importance of Distribution Reservoir
a. To balance the supply and demand in the system. In small distribution systems, variations
in demand may be three or more times the average hourly consumption.
b. To maintain adequate and fairly uniform pressure throughout the distribution system.
c. To avoid the total interruption of water service when repairing pipes between the source
of supply and the reservoir.
d. To allow pumps to be operated uniformly throughout the day. Such pumps may be much
smaller than would otherwise be required.
Reservoir
Reservoirs are constructed in elevated or hilly areas. In case of flat areas, a
supporting frame or tower is installed to support the storage tank. This is known as an (). Standpipes are reservoirs with height greater than their diameter.
Elevated Reservoir
() may be made of reinforced concrete pipe, fiber
glass, concrete hollow blocks, steel or ferro-cement. These may be single ground level tanks or
multiple type tanks.
Ground Level Reservoir
As a rule of thumb, the storage tank volume should be at least equal to one-fourth (25%) of
average day demand of the community. The formula is:
Capacity of a Reservoir
- Topography: Analyze the land contours to understand natural water flow.
- ◦ Soil Type: Determine soil permeability to assess water infiltration rates.
- ◦ Climate Data: Use historical rainfall data to estimate peak discharge and stormwater runoff.
Assessment and Planning : ◦ Site Analysis
- Land Use: Consider current and future land use in urban planning to ensure the drainage system can handle increased runoff due to urbanization.
- ◦ Environmental Impact: Ensure the system minimizes negative impacts on natural water bodies and ecosystems.
- Assessment and Planning:
◦ Urban Planning Integration
- Use methods such as the Rational Method for smaller areas or the SCS Curve Number method for larger catchments to estimate peak runoff.
- ◦ Calculate the design storm based on local rainfall intensity-duration-frequency (IDF) curves.
- Hydrological and Hydraulic Calculations:
◦ Runoff Estimation
◦ Design the drainage components (e.g., pipes, channels, culverts) to handle peak runoff
without flooding.
◦ Ensure the system can handle both minor (e.g., 2-5 year return period) and major storms
(e.g., 50-100 year return period).
- Hydrological and Hydraulic Calculations:
◦ Capacity Design
Swales and Gutters: Use grassy swales and concrete gutters to channel surface water.
◦ Catch Basins and Inlets: Place these strategically to collect runoff and convey it to the
subsurface system.
- Design Components:
◦ Surface Drainage
