hmp Flashcards
maximum rate of pumpage that can be allowed while ensuring that water-level declines are kept with acceptable limits.
Groundwater yield
maximum pumping rate that can be supplied by a well without lowering the water level in the well below the pump intake
well yield
maximum rate of withdrawal that can be sustained by the complete hydrogeologic system in a groundwater basin without causing unacceptable declines in hydraulic head in the system or causing unacceptable changes to any other component of the hydrologic cycle in the basin
basin yield
maximum rate of withdrawal that can be sustained by an aquifer without causing an unacceptable decline in the hydraulic head in the aquifer
Aquifer yield
Inflow – Outflow =
change in volume
What can observe about groundwater systems?
problems with lab methods
Conducting a pump test (theoretically)
Infrastructure
- At least one pumping well…
o K and transmissivity properties can be determined from single well tests
- At least one observation well
o To determine storage properties
- Multiple observation wells
o Better estimates of storage and transmissivity
o Boundaries
o Anisotropy
- From the test – record the pump rate and know the location of the pumping well, and observation wells.
What properties affect drawdown in an unconfined aquifer?
- Storativity
- Horizontal conductivity
- Vertical conductivity
- Specific yield
Neuman solution – Three phases of unconfined drawdown
- Phase 1: Drawdown is controlled by the Ss of the saturated part of the aquifer
- Phase 2: Drawdown is controlled by the vertical conductivity of the aquifer
- Phase 3: Drawdown is controlled by the specific yield of the aquifer
- This is called the concept of delayed yield
Three Phases System: Solid, Liquid and Gas
- Zone of aeration
- Or zone of unsaturation
- Or vadose zone
is the depression or the rise of a liquid in a small capillary passage tube having small cross sectional area such as openings in the porous materials
Capillarity
is the subsurface layer in which groundwater seeps up from a water table by capillary action to fill pores. Pores at the base of the capillary fringe are filled with water due too tension saturation
Capillary Fringe
results from 2 force: mutual attraction (Cohesion) between water molecules and the molecular attraction (Adhesion) between water and different soil materials
- Capillarity
can provide a mean of direct evaporation of ground water if the water table is close enough to the surface that the capillary fringe reaches the ground surface
- capillary fringe
measuring instrument used to determine water potential (soil moisture tension) in the vadose zone
- Device typically consists of glass or plastic tube with porous ceramic cup and filled with water
- Tensiometer
- Soil moisture at a location varies with changes in the amount of ___and _____
precipitation and evapotranspiration
when soil-moisture content of a layer reaches to the points at which the force of gravity acting on the water = the surface tension, gravity drainage cease.
- Field capacity
the remaining moisture is too tightly bound the soil particles
wilting point
primary method through which water enters an aquifer
- usually topographic high places
- deeper water table
groundwater recharge zone
an area which groundwater is discharged to the land surface, surface water, or atmosphere
- topographic lows
- shallow water table
- spring, seep, lake. or streams
- vegetation: wet soil
- arid: thicker veg cover or salt deposit
groundwater discharge zone
importance of recharge and discharge and time
important to characterize the bedding
pila nadaw edad anang tubig or unsa daw to deep well sa davao huhu
40 years
_____ wetlands, water moves from the wetland into the groundwater
recharging
____ wetlands, water moves from groundwater into the wetland
discharging
a line in a 2 dimensional groundwater flow field such that the total hydraulic head is the same everywhere on the surface
equipotential line
connects points or equal head and thus represents the height of the water table/ or potentiometeric surface of a confined aquifer, above a datum plane
equipotential line
idealized paths followed by particles of water as they move through the aquifer
- indicates recharge and discharge
flow lines
played a role in the settlement pattern of many lands
spring
spots that provide simple mechanism of springs
topographic lows
types of springs
- Depression spring -formed in unconfined aquifers when the topography intersects the water table, usually due to the surface stream incision.
- Contact spring - formed where relatively permeable rocks overlie rocks of low permeability. A lithological contact is usually marked by a line of springs. Such springs are usually associated with perched aquifers in mountains
- Fault spring - Faulting may also give rise to conditions favorable for spring formation as groundwater (at depth) under hydrostatic pressure (such as in confined aquifers) can move up along such faults. An impermeable rock unit may be brought in contact with an unconfined aquifer due to faulting.
- Sinkhole spring/solution - on karst landscapes
- Joint spring - when groundwater running along an impermeable layer of rock meets a crack (fracture) or joint in the rock.
- Fracture spring - ur due to existence of permeable fracture zones in low permeability rocks. Movement of groundwater is mainly through fractures that constitute the porosity and permeability of aquifers. Springs are formed where these fractures intersect the ground surface.
some of largest spring are found of __________
limestone bedrocks
true or false: all surface water features (streams, lakes, reservoirs, wetlands, and estuaries) interact with ground water)
true
characterized by intergranular porosity and all contain water primarily under unconfined, or water-table, conditions.
unconsolidated aquifer
a gently sloping plain consisting of alluvium
normally delimited by uplands on either side that rise above the level of the valley to varying heights
alluvial valleys
true or false: many major valley systems are products of tectonic activity rather than of fluvial or glacial erosion
true
fault-block valley can also be created by down-dropping of ____
large crustal pieces along faults
clastic sedimentary rocks are typically composed of
silicate, carbonate or clay minerals
chemically precipitated sedimentary rocks are primarily
limestone, dolomite, salt or gypsum
can also be considered to be sedimentary deposits, with the original sediments being organic
coal and lignite
true or false: it is always na sedimentary rocks occur as a single unit: there is no sequence of many beds
false
true or false: complex stratigraphy is not a hindrance to ground-water exploration
false
difficulties on studying of sedimentary rock units
change in lithology from one locality to another
can create very complex hydrogeologic systems in which determination of the locations or recharge and discharge zones and flow systems is confounded
folding and faulting of sedimentary rocks
to determine flow systems it is important to determine the ________________ and measure ____ know flow systems but ____ must also be evaluated
determine characteristics of rock units
measure groundwater levels in wells
detailed geology
based on primary permeability is a fucntion of grain size, shape, and sorting of the original sediments
- cementation
hydraulic conductivity (clastic)
desert areas receive ________ precipitation or less each year
10in (25 cm)
they are regional features, bounded on the continental side by highlands and seaward by a coastline(aquifer)
coastal-plain aquifers
exits in areas of stable basement rock as well as in those areas where the basement is sinking
may include large areas of former sea floor and the geology may be similar to that of the adjacent continental shelf
coastal plains
aquifers locted next to tidal bodies are subjected to ________-term fluctuations in the head due to the tide
short
general water balance equation
P = Q + E + /\S
P = precipitation
Q is runoff
E is evapotranspirati
/\S is the change in storage
water use and service percetage (agri, indus, domes)
Agri - 74%
Indust - 9%
dom - 17%
who regulates the water resources?
National water resource board
level of water supply service
level 1 - point source (a protected well or developed spring with an outlet but without distribution system) not more than 250 meters and user
level 2 - communal faucet system or stand post (composed of a source, reservoir, a piper distribution network and communal faucets) not more than25 meters and user farthest ha
level 3 - waterworks sysstem (waterworks system or individual house connections, household taps)
presidential decree 198
Local Water Utilities Administration (LWUA)
- provide, maintain, operate and development
surface water
temporary retention surfaces
ponds
lakes
streams
estuarine
natural depressions
groundwater
wells
springs
seepages
subterranean rivers
**
components of water supply system
water source facilities
transmission lines
treatment facilities
storage facilities
pressure zones
distribution network
source as component of Water supply system
surface water
- perennial river without impoundment
- river with impounding reservoir
shallow well depth in meters
less than 20 meters
deep well depth in meters
20 meters or more
two types of pump
positive displacement pumps and centrifugal pumps
“constant flow machines”
positve displacement pumps
velocity is added to fluid by a spinning impeller and converted to pressure energy inside the pump
centrifugal pumps
impacts of gw overextractions
land subsidence, salt water intrusions
universal solvent
water
true or false: gw usually contain largest amounts of dissolved solids
true
any deterioration in the quality of water resulting from the activities of humans
pollution of gw
most pollution of GW results from
disposal of wastes on land surface
____ and ____ of soil and rocks may affect pollutants in several way
mineral composition and physical characteristics
deterioation of water qual
changes in quality of water in aquifer and changes in well
deterioration of the biological quality
refers to the appearance of bacteria or viruses
deterioration in chemical quality
artrival at a supply well of water containing dissolved supply well of water chemical in a undersirably large concentration
important constitute in fertilizers and is present in relatively large concentration in human and animal waste
nitrate
deterioration in physical quality
changes in appearance, taste and temp
