tema 11 relaciones as as efc
Post on 17-Dec-2015
219 Views
Preview:
DESCRIPTION
TRANSCRIPT
-
Tema 11
Relacin agua superficial-agua subterrnea. Rios-acufero. Lago-acufero. Almacenamiento de ribera.
Eduardo CassiragaUniversidad Politcnica de Valencia
-
Objetivos de la clase
Objetivos de la clase
El objetivo general de esta clase es presentar las relaciones entre lasaguas superficiales y subterrnea a partir del carcter unitario del ciclohidrolgico.
Eduardo Cassiraga (UPV) Tema 5 2 / 43
-
Contenidos
Contenidos
1 Introduccin
2 Relaciones entre ros y agua subterrnea
3 Relaciones entre lagos y agua subterrnea
4 Relaciones entre humedales y agua subterrnea
5 Cambios en las relaciones aguas superficiales y aguas subterrneas
6 Conclusiones
Eduardo Cassiraga (UPV) Tema 5 3 / 43
-
Introduccin
Introduccin
La mutua interferencia entre las aguas superficiales y subterrneas esuna consecuencia lgica del carcter unitario del ciclo hidrolgico.Conocer la interaccin del agua subterrnea y superficial es esencial paralos tcnicos y gestores del agua.La gestin de una componente del ciclo hidrolgico es solo parcialmenteefectiva dado que cada componente est en continua interaccin conotras.El agua superficial est en general hidrulicamente conectada con lasubterrnea pero las interacciones entre stas son difciles de observary medir.En los siguientes ejemplos puede verse que el conocimiento de las rela-ciones aguas superficiales y subterrneas es fundamental para una efec-tiva gestin de los recursos hdricos.
Eduardo Cassiraga (UPV) Tema 5 4 / 43
-
Introduccin
Ejemplos relacionados con la cantidad de agua
Almacenamiento de agua en embalses subterrneos: las dificultadespara construir embalses superficiales (afecciones ambientales y falta delocalizaciones) potencian la posibilidad de almacenar temporalmente aguaen embalses subterrneos (uso conjunto).Afecciones a travs de la red fluvial: el agua liberada de embalses su-perficiales disminuye en volumen (infiltracin en riberas) y sufre un retrasoen su trnsito por la red fluvial, que dependen de las condiciones antece-dentes en la relacin agua superficial y subterrnea.Prdida de la atenuacin natural de avenidas: el almacenamiento enriberas, llanuras de inundacin y en humedales puede verse afectado porcambios en la relacin aguas superficiales y subterrneas (drenaje dehumedales y construccin de diques en las riberas).
Eduardo Cassiraga (UPV) Tema 5 5 / 43
-
Introduccin
Ejemplos relacionados con la calidad de agua
Acuferos poco profundos contaminados: determinacin de los efectosde la contaminacin por acuferos superficiales contaminados de ros ylagos.Diferencias entre las cuencas superficiales y subterrneas: ante lanecesidad de tratar de forma conjunta las aguas superficiales y subterr-neas, surgen dificultades para integrar el sistema de escorrenta subterr-nea en la clsica aproximacin al sistema superficial (cuenca hidrogrfica)por la no coincidencia entre cuencas superficiales y subterrneas.Posibilidad de beber el agua subterrnea sin tratamiento alguno: engeneral suele asumirse que el agua subterrnea se puede beber sin tra-tamiento alguno pero esto puede no ser as si los pozos de extraccin seencuentran cerca de corrientes superficiales potencialmente contamina-das.
Eduardo Cassiraga (UPV) Tema 5 6 / 43
-
Introduccin
Ejemplos en relacin al medio ambiente acutico
Caractersticas qumicas diferentes de las aguas subterrneas y su-perficiales: la mezcla de agua superficial y subterrnea puede afectar losecosistemas acuticos si con ella se alteran factores como la acidez, latemperatura y el oxgeno disuelto.Estudio de la calidad de agua a partir de la fauna en la interfaz aguasuperficial y agua subterrnea: indicaciones de la calidad del agua y decambios adversos en los ecosistemas acuticos pueden inferirse a travsdel estudio de la fauna en la interfaz agua superficial y subterrnea.Permanencia de humedales: muchos humedales dependen de la exis-tencia de un flujo de agua subterrnea estable.Caractersticas qumicas del agua descargada a un nuevo humedal:el xito de la creacin de nuevos humedales en lugares donde existieronotros requiere de un contexto hidrogeolgico similar al de los segundos.
Eduardo Cassiraga (UPV) Tema 5 7 / 43
-
Relaciones entre ros y agua subterrnea
Relaciones entre ros y agua subterrnea
La interaccin entre las corrientes superficiales y el agua subterrneatiene lugar de tres formas diferentes, que son:
Ro ganador.Ro perdedor.Ro efmero.
Eduardo Cassiraga (UPV) Tema 5 8 / 43
-
Relaciones entre ros y agua subterrnea Ro ganador
Ro ganador
Un ro es ganador cuando existe un flujo de agua desde el acuferohacia el ro.
El nivel piezomtrico en la vecin-dad del ro se encuentra ms altoque la superficie de agua del cau-ce.Esta situacin es habitual en zo-nas templadas hmedas y es larelacin tipo que se suele reflejaren los tratados clsicos de Hidro-loga.Las lneas de nivel piezomtricocortan la corriente en direccinaguas arriba.
9
INTERACTION OF GROUND WATER AND STREAMS
Streams interact with ground water in all types of landscapes (see Box B). The interaction takes place in three basic ways: streams gain water from inflow of ground water through the streambed (gaining stream, Figure 8A), they lose water to ground water by outflow through the stre-ambed (losing stream, Figure 9A), or they do both, gaining in some reaches and losing in other reaches. For ground water to discharge into a stream channel, the altitude of the water table in the vicinity of the stream must be higher than the alti-
tude of the stream-water surface. Conversely, for surface water to seep to ground water, the altitude of the water table in the vicinity of the stream must be lower than the altitude of the stream-water surface. Contours of water-table elevation indicate gaining streams by pointing in an upstream direc-tion (Figure 8B), and they indicate losing streams by pointing in a downstream direction (Figure 9B) in the immediate vicinity of the stream.
Losing streams can be connected to the ground-water system by a continuous saturated zone (Figure 9A) or can be disconnected from
GAINING STREAM
Flow direction
Unsaturated zone
Water table
Shallow aquifer
A
Str
eam
Ground-water flow line
B
70
50
50
40
40 30
30
20
20
60
60Water-table c
ontour
Figure 8. Gaining streams receive water from the ground-water system (A). This can be determined from water-table contour maps because the contour lines point in the upstream direction where they cross the stream (B).
Figure 9. Losing streams lose water to the ground-water system (A). This can be determined from water-table contour maps because the contour lines point in the downstream direction where they cross the stream (B).
B
Str
eam
100
90
80
70
Ground-water flow line
Water-table
contour
LOSING STREAM
Flow direction
Water table Unsaturatedzone
A
Eduardo Cassiraga (UPV) Tema 5 9 / 43
-
Relaciones entre ros y agua subterrnea Ro ganador
Ro ganador
En ausencia de escorren-ta directa o superficial enlos periodos entre episo-dios de lluvia, el flujo basede los ros proviene funda-mentalmente del almace-namiento de los acuferos.La proporcin de agua enun ro que proviene de losacuferos es variable y de-pende de las condicio-nes fisiogrficas y clim-ticas.
12
BThe Ground-Water Component
of StreamflowGround water contributes to streams in most physio-
graphic and climatic settings. Even in settings where streams are primarily losing water to ground water, certain reaches may receive ground-water inflow during some seasons. The proportion of stream water that is derived from ground-water inflow varies across physiographic and climatic settings. The amount of water that ground water contributes to streams can be estimated by analyzing streamflow hydrographs to deter-mine the ground-water component, which is termed base flow (Figure B1). Several different methods of analyzing hydro-graphs have been used by hydrologists to determine the base-flow component of streamflow.
One of the methods, which provides a conservative estimate of base flow, was used to determine the ground-water contribution to streamflow in 24 regions in the contermi-nous United States. The regions, delineated on the basis of physiography and climate, are believed to have common characteristics with respect to the interactions of ground water and surface water (Figure B2). Fifty-four streams were selected for the analysis, at least two in each of the
24 regions. Streams were selected that had drainage basins less than 250 square miles and that had less than 3 percent of the drainage area covered by lakes and wetlands. Daily streamflow values for the 30-year period, 19611990, were used for the analysis of each stream. The analysis indicated that, for the 54 streams over the 30-year period, an average of 52 percent of the streamflow was contributed by ground water. Ground-water contributions ranged from 14 percent to 90 percent, and the median was 55 percent. The ground-water contribution to streamflow for selected streams can be compared in Figure B2. As an example of the effect that geologic setting has on the contribution of ground water to streamflow, the Forest River in North Dakota can be compared to the Sturgeon River in Michigan. The Forest River Basin is underlain by poorly permeable silt and clay deposits, and only about 14 percent of its average annual flow is contributed by ground water; in contrast, the Sturgeon River Basin is underlain by highly permeable sand and gravel, and about 90 percent of its average annual flow is contributed by ground water.
Total streamflowBase flow
11 4121 61 101 141 181 221 261 301 34181 121 161 201 241 281 321 361
10
100
1,000
10,000
100,000
FLO
W, I
N C
UB
IC F
EE
T P
ER
SE
CO
ND
TIME, IN DAYS
Figure B1. The ground-water compo-nent of streamflow was estimated from a streamflow hydrograph for the Homochitto River in Mississippi, using a method developed by the institute of Hydrology, United Kingdom. (Institute of Hydrology, 1980, Low flow studies: Wallingford, Oxon, United Kingdom, Research Report No. 1.)
Dicha cantidad se estima analizando los hidrogramas de flujo anual opara un evento del ro estudiado.
Eduardo Cassiraga (UPV) Tema 5 10 / 43
-
Relaciones entre ros y agua subterrnea Ro perdedor
Ro perdedor
Un ro perdedor alimenta al acufero pudiendo estar o no hidrulicamenteconectado con l.La situacin de ro perdedor es t-pica de las zonas ridas en lasque la recarga es pequea.Las lneas de nivel piezomtricocortan la corriente en direccinaguas abajo.Que el nivel del acufero este pordebajo del nivel del ro perdedorpuede deberse a condiciones na-turales, por ejemplo, que la pen-diente longitudinal del lecho seamayor que la del nivel piezomtri-co.
9
INTERACTION OF GROUND WATER AND STREAMS
Streams interact with ground water in all types of landscapes (see Box B). The interaction takes place in three basic ways: streams gain water from inflow of ground water through the streambed (gaining stream, Figure 8A), they lose water to ground water by outflow through the stre-ambed (losing stream, Figure 9A), or they do both, gaining in some reaches and losing in other reaches. For ground water to discharge into a stream channel, the altitude of the water table in the vicinity of the stream must be higher than the alti-
tude of the stream-water surface. Conversely, for surface water to seep to ground water, the altitude of the water table in the vicinity of the stream must be lower than the altitude of the stream-water surface. Contours of water-table elevation indicate gaining streams by pointing in an upstream direc-tion (Figure 8B), and they indicate losing streams by pointing in a downstream direction (Figure 9B) in the immediate vicinity of the stream.
Losing streams can be connected to the ground-water system by a continuous saturated zone (Figure 9A) or can be disconnected from
GAINING STREAM
Flow direction
Unsaturated zone
Water table
Shallow aquifer
A
Str
eam
Ground-water flow line
B
70
50
50
40
40 30
30
20
20
60
60Water-table c
ontour
Figure 8. Gaining streams receive water from the ground-water system (A). This can be determined from water-table contour maps because the contour lines point in the upstream direction where they cross the stream (B).
Figure 9. Losing streams lose water to the ground-water system (A). This can be determined from water-table contour maps because the contour lines point in the downstream direction where they cross the stream (B).
Str
eam
100
90
80
70
Ground-water flow line
Water-table
contour
LOSING STREAM
Flow direction
Water table Unsaturatedzone
A
Eduardo Cassiraga (UPV) Tema 5 11 / 43
-
Relaciones entre ros y agua subterrnea Ro perdedor
Ro perdedor
Tambin puede ser consecuencia de que un ro ganador pueda recibirmenos agua del acufero por la explotacin de aguas subterrneas, lle-gando incluso a ser perdedor.En acuferos muy permeables, aunque la recarga del acufero sea im-portante, tambin puede suceder que los niveles resultantes estn pordebajo del cauce principal y el ro sea perdedor.Cuando los niveles del agua subterrnea se encuentran por debajo dellecho del ro, ste y el acufero estn desconectados.
El flujo que atraviesa la capa se-mipermeable del lecho dependedel calado del ro, de su espesory de su conductividad hidrulica(efecto ducha).
10
the ground-water system by an unsaturated zone. Where the stream is disconnected from the ground-water system by an unsaturated zone, the water table may have a discernible mound below the stream (Figure 10) if the rate of recharge through the streambed and unsaturated zone is greater than the rate of lateral ground-water flow away from the water-table mound. An important feature of streams that are disconnected from ground water is that pumping of shallow ground water near the stream does not affect the flow of the stream near the pumped wells.
In some environments, streamflow gain or loss can persist; that is, a stream might always gain water from ground water, or it might always lose water to ground water. However, in other envi-
ronments, flow direction can vary a great deal along a stream; some reaches receive ground water, and other reaches lose water to ground water. Furthermore, flow direction can change in very short timeframes as a result of individual storms causing focused recharge near the stream-bank, temporary flood peaks moving down the channel, or transpiration of ground water by streamside vegetation.
A type of interaction between ground water and streams that takes place in nearly all streams at one time or another is a rapid rise in stream stage that causes water to move from the stream into the streambanks. This process, termed bank storage (Figures 11 and 12B), usually is caused by storm precipitation, rapid snowmelt, or release of water
DISCONNECTED STREAM
Flow direction
Water table
Unsaturatedzone
Figure 11. If stream levels rise higher than adjacent ground-water levels, stream water moves into the streambanks as bank storage.
BANK STORAGE
Flow direction
Water tableduring base flow
Bank storage
High stage
Water table athigh stage
Figure 10. Disconnected streams are separated from the ground-water system by an unsaturated zone.
Streams interact with ground water in three basic ways: streams gain
water from inflow of ground water through the streambed (gaining stream),
they lose water to ground water by outflow through the streambed (losing stream), or
they do both, gaining in some reaches and losing in other reaches
El flujo hacia el acufero es no saturado, estando el grado de saturacindel medio determinado por el caudal que pierde el ro.
Eduardo Cassiraga (UPV) Tema 5 12 / 43
-
Relaciones entre ros y agua subterrnea Ro efmero
Ro efmero
Un ro efmero es aquel que fluye nicamente como respuesta a lluviasintensas.La altura del nivel de agua en los acuferos est siempre bajo el niveldel cauce y normalmente muy por debajo de l.Son ros perdedores que en situacin de avenidas pierden agua que re-carga al acufero.La existencia de ros efmeros es comn en cuencas ridas y semiri-das.Debido a la poca recarga los niveles del acufero estn bajos y loslechos de los cauces estn por encima de ellos en toda su longitud,excepto en las zonas ms aguas abajo, en zonas muy llanas cerca de loslmites del acufero o en las zonas en que los acuferos son superficialesy tienen muy poco espesor.
Eduardo Cassiraga (UPV) Tema 5 13 / 43
-
Relaciones entre ros y agua subterrnea Ro efmero
Ro efmero
Los tramos altos de ros con grandes pendientes pueden ser efmerosincluso en cuencas hmedas.En zonas con permeabilidad grande se precisa menos pendiente en elnivel fretico para trasmitir la misma recarga y pueden quedar desconec-tados del acufero ms tramos de ro.Puede haber cauces intermi-tentes ocasionados por las os-cilaciones regionales del ni-vel fretico.El ro se seca cuando el nivelfretico del acufero est bajoel lecho del cauce y drena alacufero cuando est por enci-ma de l en periodos hmedos.
Precipitacin
Lmite delrea debalance
Nivel piezomtrico
Eduardo Cassiraga (UPV) Tema 5 14 / 43
-
Relaciones entre lagos y agua subterrnea
Relaciones entre lagos y agua subterrnea
En relacin al agua subterrnea, los lagos pueden ser ganadores, per-dedores o ambas cosas a la vez.
18
INTERACTION OF GROUND WATER AND LAKES
Lakes interact with ground water in three basic ways: some receive ground-water inflow throughout their entire bed; some have seepage loss to ground water throughout their entire bed; but perhaps most lakes receive ground-water inflow through part of their bed and have seepage loss to ground water through other parts (Figure 16). Although these basic interactions are the same for lakes as they are for streams, the inter-actions differ in several ways.
The water level of natural lakes, that is, those not controlled by dams, generally does not change as rapidly as the water level of streams; therefore, bank storage is of lesser importance in lakes than it is in streams. Evaporation generally has a greater effect on lake levels than on stream levels because the surface area of lakes is generally larger and less shaded than many reaches of streams, and because lake water is not replenished as readily as a reach of a stream. Lakes can be present in many different parts of the landscape and can have complex ground-water flow systems associated with them. This is especially true for lakes in glacial and dune terrain, as is discussed in a later section of this Circular. Furthermore, lake sediments commonly have greater volumes of organic deposits than streams. These poorly perme-able organic deposits can affect the distribution of seepage and biogeochemical exchanges of water and solutes more in lakes than in streams.
Reservoirs are human-made lakes that are designed primarily to control the flow and distribu-tion of surface water. Most reservoirs are constructed in stream valleys; therefore, they have some characteristics both of streams and lakes. Like streams, reservoirs can have widely fluctuating levels, bank storage can be significant, and they commonly have a continuous flushing of water through them. Like lakes, reservoirs can have significant loss of water by evaporation, significant cycling of chemical and biological materials within their waters, and extensive biogeochemical exchanges of solutes with organic sediments.
B
Lake surface
A
Lake surface
C
Lake surface
Figure 16. Lakes can receive ground-water inflow (A), lose water as seepage to ground water (B), or both
18
INTERACTION OF GROUND WATER AND LAKES
Lakes interact with ground water in three basic ways: some receive ground-water inflow throughout their entire bed; some have seepage loss to ground water throughout their entire bed; but perhaps most lakes receive ground-water inflow through part of their bed and have seepage loss to ground water through other parts (Figure 16). Although these basic interactions are the same for lakes as they are for streams, the inter-actions differ in several ways.
The water level of natural lakes, that is, those not controlled by dams, generally does not change as rapidly as the water level of streams; therefore, bank storage is of lesser importance in lakes than it is in streams. Evaporation generally has a greater effect on lake levels than on stream levels because the surface area of lakes is generally larger and less shaded than many reaches of streams, and because lake water is not replenished as readily as a reach of a stream. Lakes can be present in many different parts of the landscape and can have complex ground-water flow systems associated with them. This is especially true for lakes in glacial and dune terrain, as is discussed in a later section of this Circular. Furthermore, lake sediments commonly have greater volumes of organic deposits than streams. These poorly perme-able organic deposits can affect the distribution of seepage and biogeochemical exchanges of water and solutes more in lakes than in streams.
Reservoirs are human-made lakes that are designed primarily to control the flow and distribu-tion of surface water. Most reservoirs are constructed in stream valleys; therefore, they have some characteristics both of streams and lakes. Like streams, reservoirs can have widely fluctuating levels, bank storage can be significant, and they commonly have a continuous flushing of water through them. Like lakes, reservoirs can have significant loss of water by evaporation, significant cycling of chemical and biological materials within their waters, and extensive biogeochemical exchanges of solutes with organic sediments.
B
Lake surface
A
Lake surface
C
Lake surface
Figure 16. Lakes can receive ground-water inflow (A), lose water as seepage to ground water (B), or both
18
INTERACTION OF GROUND WATER AND LAKES
Lakes interact with ground water in three basic ways: some receive ground-water inflow throughout their entire bed; some have seepage loss to ground water throughout their entire bed; but perhaps most lakes receive ground-water inflow through part of their bed and have seepage loss to ground water through other parts (Figure 16). Although these basic interactions are the same for lakes as they are for streams, the inter-actions differ in several ways.
The water level of natural lakes, that is, those not controlled by dams, generally does not change as rapidly as the water level of streams; therefore, bank storage is of lesser importance in lakes than it is in streams. Evaporation generally has a greater effect on lake levels than on stream levels because the surface area of lakes is generally larger and less shaded than many reaches of streams, and because lake water is not replenished as readily as a reach of a stream. Lakes can be present in many different parts of the landscape and can have complex ground-water flow systems associated with them. This is especially true for lakes in glacial and dune terrain, as is discussed in a later section of this Circular. Furthermore, lake sediments commonly have greater volumes of organic deposits than streams. These poorly perme-able organic deposits can affect the distribution of seepage and biogeochemical exchanges of water and solutes more in lakes than in streams.
Reservoirs are human-made lakes that are designed primarily to control the flow and distribu-tion of surface water. Most reservoirs are constructed in stream valleys; therefore, they have some characteristics both of streams and lakes. Like streams, reservoirs can have widely fluctuating levels, bank storage can be significant, and they commonly have a continuous flushing of water through them. Like lakes, reservoirs can have significant loss of water by evaporation, significant cycling of chemical and biological materials within their waters, and extensive biogeochemical exchanges of solutes with organic sediments.
B
Lake surface
A
Lake surface
C
Lake surface
Figure 16. Lakes can receive ground-water inflow (A), lose water as seepage to ground water (B), or both
Eduardo Cassiraga (UPV) Tema 5 15 / 43
-
Relaciones entre lagos y agua subterrnea
Relaciones entre lagos y agua subterrnea
El almacenamiento en riberas no es importante en lagos ya que el nivelde agua no es variable como en los ros.Los efectos de la evaporacin son mayores en los lagos.Los sedimentos de los lagos tienen un mayor volumen de depsitosorgnicos poco permeables que afectan la relacin aguas superficialesy subterrneas.Los embalses son lagos construidos por el hombre en determinadas zo-nas de un cauce y por tanto tienen algunas caractersticas de los ros(niveles variables, almacenamiento en riberas importante, prdidas porevaporacin, etc.)
Eduardo Cassiraga (UPV) Tema 5 16 / 43
-
Relaciones entre humedales y agua subterrnea
Relaciones entre humedales y agua subterrnea
Los humedales se pueden formar a partir de la descarga del agua sub-terrnea a la superficie del terreno, por afloramiento del nivel piezo-mtrico en taludes, a partir de cauces superficiales y por causa de laprecipitacin.
20
Wetlands in riverine and coastal areas have especially complex hydrological interactions because they are subject to periodic water-level changes. Some wetlands in coastal areas are affected by very predictable tidal cycles. Other coastal wetlands and riverine wetlands are more affected by seasonal water-level changes and by flooding. The combined effects of precipitation, evapotranspiration, and interaction with surface water and ground water result in a pattern of water depths in wetlands that is distinctive.
Hydroperiod is a term commonly used in wetland science that refers to the amplitude and frequency of water-level fluctuations. Hydro-period affects all wetland characteristics, including the type of vegetation, nutrient cycling, and the types of invertebrates, fish, and bird species present.
ACOMPLEX FLOW FIELDS
Area favorable forwetland formation
Direction ofground-water
flow
Water table
Line of equalhydraulic
head
Water table
SEEPAGE FACE
BREAK IN SLOPE
Land surface
Land surface
Zone of high permeabilityZone of low permeability
Direction of ground-water flow
Areas favorable forwetland formation
Wetland
Wetland
Water ta
ble
Land surface
Land surface
Water table
Direction of ground-water flow
Direction of ground-water flow
Stream
Figure 17. The source of water to wetlands can be from ground-water discharge where the land surface is underlain by complex ground-water flow fields (A), from ground-water discharge at seepage faces and at breaks in slope of the water table (B), from streams (C), and from precipitation in cases where wetlands have no stream inflow and ground-water gradients slope away from the wetland (D).
20
Wetlands in riverine and coastal areas have especially complex hydrological interactions because they are subject to periodic water-level changes. Some wetlands in coastal areas are affected by very predictable tidal cycles. Other coastal wetlands and riverine wetlands are more affected by seasonal water-level changes and by flooding. The combined effects of precipitation, evapotranspiration, and interaction with surface water and ground water result in a pattern of water depths in wetlands that is distinctive.
Hydroperiod is a term commonly used in wetland science that refers to the amplitude and frequency of water-level fluctuations. Hydro-period affects all wetland characteristics, including the type of vegetation, nutrient cycling, and the types of invertebrates, fish, and bird species present.
ACOMPLEX FLOW FIELDS
Area favorable forwetland formation
Direction ofground-water
flow
Water table
Line of equalhydraulic
head
Water table
SEEPAGE FACE
BREAK IN SLOPE
Land surface
Land surface
Zone of high permeabilityZone of low permeability
Direction of ground-water flow
Areas favorable forwetland formation
Wetland
Wetland
Water ta
ble
Land surface
Land surface
Water table
Direction of ground-water flow
Direction of ground-water flow
Stream
Figure 17. The source of water to wetlands can be from ground-water discharge where the land surface is underlain by complex ground-water flow fields (A), from ground-water discharge at seepage faces and at breaks in slope of the water table (B), from streams (C), and from precipitation in cases where wetlands have no stream inflow and ground-water gradients slope away from the wetland (D).
20
Wetlands in riverine and coastal areas have especially complex hydrological interactions because they are subject to periodic water-level changes. Some wetlands in coastal areas are affected by very predictable tidal cycles. Other coastal wetlands and riverine wetlands are more affected by seasonal water-level changes and by flooding. The combined effects of precipitation, evapotranspiration, and interaction with surface water and ground water result in a pattern of water depths in wetlands that is distinctive.
Hydroperiod is a term commonly used in wetland science that refers to the amplitude and frequency of water-level fluctuations. Hydro-period affects all wetland characteristics, including the type of vegetation, nutrient cycling, and the types of invertebrates, fish, and bird species present.
ACOMPLEX FLOW FIELDS
Area favorable forwetland formation
Direction ofground-water
flow
Water table
Line of equalhydraulic
head
Water table
SEEPAGE FACE
BREAK IN SLOPE
Land surface
Land surface
Zone of high permeabilityZone of low permeability
Direction of ground-water flow
Areas favorable forwetland formation
Wetland
Wetland
Water ta
ble
Land surface
Land surface
Water table
Direction of ground-water flow
Direction of ground-water flow
Stream
Figure 17. The source of water to wetlands can be from ground-water discharge where the land surface is underlain by complex ground-water flow fields (A), from ground-water discharge at seepage faces and at breaks in slope of the water table (B), from streams (C), and from precipitation in cases where wetlands have no stream inflow and ground-water gradients slope away from the wetland (D).
20
Wetlands in riverine and coastal areas have especially complex hydrological interactions because they are subject to periodic water-level changes. Some wetlands in coastal areas are affected by very predictable tidal cycles. Other coastal wetlands and riverine wetlands are more affected by seasonal water-level changes and by flooding. The combined effects of precipitation, evapotranspiration, and interaction with surface water and ground water result in a pattern of water depths in wetlands that is distinctive.
Hydroperiod is a term commonly used in wetland science that refers to the amplitude and frequency of water-level fluctuations. Hydro-period affects all wetland characteristics, including the type of vegetation, nutrient cycling, and the types of invertebrates, fish, and bird species present.
ACOMPLEX FLOW FIELDS
Area favorable forwetland formation
Direction ofground-water
flow
Water table
Line of equalhydraulic
head
Water table
SEEPAGE FACE
BREAK IN SLOPE
Land surface
Land surface
Zone of high permeabilityZone of low permeability
Direction of ground-water flow
Areas favorable forwetland formation
Wetland
Wetland
Water ta
ble
Land surface
Land surface
Water table
Direction of ground-water flow
Direction of ground-water flow
Stream
Figure 17. The source of water to wetlands can be from ground-water discharge where the land surface is underlain by complex ground-water flow fields (A), from ground-water discharge at seepage faces and at breaks in slope of the water table (B), from streams (C), and from precipitation in cases where wetlands have no stream inflow and ground-water gradients slope away from the wetland (D).
Eduardo Cassiraga (UPV) Tema 5 17 / 43
-
Relaciones entre humedales y agua subterrnea
Relaciones entre humedales y agua subterrnea
De manera similar a los ros y los lagos, los humedales pueden ser gana-dores, perdedores o ambas cosas a la vez.En humedales a partir de cauces superficiales el agua subterrnea aportasolutos en ella disueltos.En el caso de humedales originados por la precipitacin, los componen-tes qumicos dependen de la lluvia.Muchos humedales estn presentes a lo largo de corrientes cuanto lavelocidad del agua es baja.Los humedales en riveras y costas estn fuertemente afectados por lasfluctuaciones peridicas del nivel del agua (hidroperiodo).En los lagos la transferencia agua superficial-agua subterrnea a travsde sus bordes es ms rpida que en humedales por el efecto de lascontinuas ondas.En los lechos en cambio, las races de la vegetacin, hace que el inter-cambio de agua sea ms fcil en los humedales.
Eduardo Cassiraga (UPV) Tema 5 18 / 43
-
Cambios en las relaciones aguas superficiales y aguas subterrneas
Cambios en las relaciones aguas sup. y aguas sub.
En muchas situaciones la condicin de ro no se modifica.Sin embargo, por razones naturales o humanas, en ocasiones la direc-cin de flujo puede verse afectada e incluso la condicin del ro modifi-cada.Se analizan los efectos de o del:
Una avenida en el almacenamiento en riberas.La distribucin de la recarga en zonas altas del cauce.Un cambio abrupto en la pendiente del cauce.Los meandros del cauce.El desarrollo agrcola.El desarrollo urbano e industrial.El drenaje de terrenos.Las modificaciones del valle de los ros.La accin de perforaciones.Las modificaciones en la atmsfera.
Eduardo Cassiraga (UPV) Tema 5 19 / 43
-
Cambios en las relaciones aguas superficiales y aguas subterrneas Efecto de una avenida en el almacenamiento en riberas
Avenidas y almacenamiento en riberas
Las avenidas al poder modificar las caractersticas del lecho semipermea-ble pueden cambiar cuantitativamente la relacin ro-acufero.Un ro ganador puede infiltrar agua al acufero cuando su nivel en aveni-das est por encima del nivel fretico y pasar a ser perdedor.La mayor parte del volumen de agua recargada por el ro en este procesopermanece durante un tiempo limitado en el acufero, semanas o meses,antes de volver otra vez al ro.El almacenamiento en riberas de-be ser considerado especialmen-te en ros con oscilaciones im-portantes de calado y conecta-dos con acuferos con permea-bilidad media o alta.
10
the ground-water system by an unsaturated zone. Where the stream is disconnected from the ground-water system by an unsaturated zone, the water table may have a discernible mound below the stream (Figure 10) if the rate of recharge through the streambed and unsaturated zone is greater than the rate of lateral ground-water flow away from the water-table mound. An important feature of streams that are disconnected from ground water is that pumping of shallow ground water near the stream does not affect the flow of the stream near the pumped wells.
In some environments, streamflow gain or loss can persist; that is, a stream might always gain water from ground water, or it might always lose water to ground water. However, in other envi-
ronments, flow direction can vary a great deal along a stream; some reaches receive ground water, and other reaches lose water to ground water. Furthermore, flow direction can change in very short timeframes as a result of individual storms causing focused recharge near the stream-bank, temporary flood peaks moving down the channel, or transpiration of ground water by streamside vegetation.
A type of interaction between ground water and streams that takes place in nearly all streams at one time or another is a rapid rise in stream stage that causes water to move from the stream into the streambanks. This process, termed bank storage (Figures 11 and 12B), usually is caused by storm precipitation, rapid snowmelt, or release of water
DISCONNECTED STREAM
Flow direction
Water table
Unsaturatedzone
Figure 11. If stream levels rise higher than adjacent ground-water levels, stream water moves into the streambanks as bank storage.
BANK STORAGE
Flow direction
Water tableduring base flow
Bank storage
High stage
Water table athigh stage
Figure 10. Disconnected streams are separated from the ground-water system by an unsaturated zone.
Streams interact with ground water in three basic ways: streams gain
water from inflow of ground water through the streambed (gaining stream),
they lose water to ground water by outflow through the streambed (losing stream), or
they do both, gaining in some reaches and losing in other reaches
Eduardo Cassiraga (UPV) Tema 5 20 / 43
-
Cambios en las relaciones aguas superficiales y aguas subterrneas Efecto de una avenida en el almacenamiento en riberas
Avenidas y almacenamiento en riberas
Antes de la avenida la situacin esla de ro ganador.Si la avenida no es suficiente pa-ra anegar la planicie de inunda-cin, el agua recarga las riberas(ro perdedor) y retorna al ro enalgunos das o semanas.Si la avenida inunda una zona msalejada del cauce, el agua recargalas riberas y las planicies de inun-dacin pudiendo tardar meses oaos en retornar al ro.El efecto de la reduccin de flujodel ro atena y retrasa el pico dela crecida.
11
from a reservoir upstream. As long as the rise in stage does not overtop the streambanks, most of the volume of stream water that enters the streambanks returns to the stream within a few days or weeks. The loss of stream water to bank storage and return of this water to the stream in a period of days or weeks tends to reduce flood peaks and later supple-ment stream flows. If the rise in stream stage is sufficient to overtop the banks and flood large areas of the land surface, widespread recharge to the water table can take place throughout the flooded area (Figure 12C). In this case, the time it takes for the recharged floodwater to return to the stream by ground-water flow may be weeks, months, or years because the lengths of the ground-water flow paths are much longer than those resulting from local bank storage. Depending on the frequency, magnitude, and intensity of storms and on the related magnitude of increases in stream stage, some streams and adjacent shallow aquifers may be in a continuous readjustment from interac-tions related to bank storage and overbank flooding.
In addition to bank storage, other processes may affect the local exchange of water between streams and adjacent shallow aquifers. Changes in streamflow between gaining and losing condi-tions can also be caused by pumping ground water
near streams (see Box C). Pumping can intercept ground water that would otherwise have discharged to a gaining stream, or at higher pumping rates it can induce flow from the stream to the aquifer.
1
2
1
2
3
Original water t
able
Original water t
able
1
EXPLANATION
Sequential stream stages
Approximate direction of ground- water flow or recharge through the unsaturated zone
1 2 3
B
A
C
Streambank
Land surface(flood plain)
Streambed
Original water t
able
Figure 12. If stream levels rise higher than their streambanks (C), the floodwaters recharge ground water throughout the flooded areas.
11
from a reservoir upstream. As long as the rise in stage does not overtop the streambanks, most of the volume of stream water that enters the streambanks returns to the stream within a few days or weeks. The loss of stream water to bank storage and return of this water to the stream in a period of days or weeks tends to reduce flood peaks and later supple-ment stream flows. If the rise in stream stage is sufficient to overtop the banks and flood large areas of the land surface, widespread recharge to the water table can take place throughout the flooded area (Figure 12C). In this case, the time it takes for the recharged floodwater to return to the stream by ground-water flow may be weeks, months, or years because the lengths of the ground-water flow paths are much longer than those resulting from local bank storage. Depending on the frequency, magnitude, and intensity of storms and on the related magnitude of increases in stream stage, some streams and adjacent shallow aquifers may be in a continuous readjustment from interac-tions related to bank storage and overbank flooding.
In addition to bank storage, other processes may affect the local exchange of water between streams and adjacent shallow aquifers. Changes in streamflow between gaining and losing condi-tions can also be caused by pumping ground water
near streams (see Box C). Pumping can intercept ground water that would otherwise have discharged to a gaining stream, or at higher pumping rates it can induce flow from the stream to the aquifer.
1
2
1
2
3
Original water t
able
Original water t
able
1
EXPLANATION
Sequential stream stages
Approximate direction of ground- water flow or recharge through the unsaturated zone
1 2 3
B
A
C
Streambank
Land surface(flood plain)
Streambed
Original water t
able
Figure 12. If stream levels rise higher than their streambanks (C), the floodwaters recharge ground water throughout the flooded areas.
11
from a reservoir upstream. As long as the rise in stage does not overtop the streambanks, most of the volume of stream water that enters the streambanks returns to the stream within a few days or weeks. The loss of stream water to bank storage and return of this water to the stream in a period of days or weeks tends to reduce flood peaks and later supple-ment stream flows. If the rise in stream stage is sufficient to overtop the banks and flood large areas of the land surface, widespread recharge to the water table can take place throughout the flooded area (Figure 12C). In this case, the time it takes for the recharged floodwater to return to the stream by ground-water flow may be weeks, months, or years because the lengths of the ground-water flow paths are much longer than those resulting from local bank storage. Depending on the frequency, magnitude, and intensity of storms and on the related magnitude of increases in stream stage, some streams and adjacent shallow aquifers may be in a continuous readjustment from interac-tions related to bank storage and overbank flooding.
In addition to bank storage, other processes may affect the local exchange of water between streams and adjacent shallow aquifers. Changes in streamflow between gaining and losing condi-tions can also be caused by pumping ground water
near streams (see Box C). Pumping can intercept ground water that would otherwise have discharged to a gaining stream, or at higher pumping rates it can induce flow from the stream to the aquifer.
1
2
1
2
3
Original water t
able
Original water t
able
1
EXPLANATION
Sequential stream stages
Approximate direction of ground- water flow or recharge through the unsaturated zone
1 2 3
B
A
C
Streambank
Land surface(flood plain)
Streambed
Original water t
able
Figure 12. If stream levels rise higher than their streambanks (C), the floodwaters recharge ground water throughout the flooded areas.
Eduardo Cassiraga (UPV) Tema 5 21 / 43
-
Cambios en las relaciones aguas superficiales y aguas subterrneas Efecto de la distribucin de la recarga en zonas altas del cauce
Distribucin de la recarga
La distribucin de la recargapuede afectar el punto de co-nexin ro acufero.Si el cauce se genera en zo-nas altas de la cuenca podrapermanecer seco gran partedel ao.Solo llevara agua en presen-cia de precipitaciones o fu-sin de nieve.
16
Where streamflow is generated in head-waters areas, the changes in streamflow between gaining and losing conditions may be particularly variable (Figure 13). The headwaters segment of streams can be completely dry except during storm events or during certain seasons of the year when snowmelt or precipitation is sufficient to maintain continuous flow for days or weeks. During these times, the stream will lose water to the unsaturated zone beneath its bed. However, as the water table rises through recharge in the headwaters area, the losing reach may become a gaining reach as the water table rises above the level of the stream. Under these conditions, the point where ground water first contributes to the stream gradually moves upstream.
Some gaining streams have reaches that lose water to the aquifer under normal conditions of streamflow. The direction of seepage through the bed of these streams commonly is related to abrupt changes in the slope of the streambed (Figure 14A) or to meanders in the stream channel (Figure 14B). For example, a losing stream reach
usually is located at the downstream end of pools in pool and riffle streams (Figure 14A), or upstream from channel bends in meandering streams (Figure 14B). The subsurface zone where stream water flows through short segments of its adjacent bed and banks is referred to as the hyporheic zone. The size and geometry of hyporheic zones surrounding streams vary greatly in time and space. Because of mixing between ground water and surface water in the hyporheic zone, the chemical and biological character of the hyporheic zone may differ markedly from adjacent surface water and ground water.
Ground-water systems that discharge to streams can underlie extensive areas of the land surface (Figure 15). As a result, environmental conditions at the interface between ground water and surface water reflect changes in the broader landscape. For example, the types and numbers of organisms in a given reach of streambed result, in part, from interactions between water in the hyporheic zone and ground water from distant sources.
Unsaturatedzone
Saturated zone
Stream surface
Water table Flowing (gaining) stream
Location ofstart of flow
of stream
Unsaturatedzone
Saturated zone
Stream surface
Water table Flowing (gaining) stream
Location ofstart of flow
of stream
A
B
Streambed
Streambed
Streambed
Streambed
Figure 13. The location where peren-nial streamflow begins in a channel can vary depending on the distribution of recharge in headwaters areas. Following dry periods (A), the start of streamflow will move up-channel during wet periods as the ground-water system becomes more saturated (B).
16
Where streamflow is generated in head-waters areas, the changes in streamflow between gaining and losing conditions may be particularly variable (Figure 13). The headwaters segment of streams can be completely dry except during storm events or during certain seasons of the year when snowmelt or precipitation is sufficient to maintain continuous flow for days or weeks. During these times, the stream will lose water to the unsaturated zone beneath its bed. However, as the water table rises through recharge in the headwaters area, the losing reach may become a gaining reach as the water table rises above the level of the stream. Under these conditions, the point where ground water first contributes to the stream gradually moves upstream.
Some gaining streams have reaches that lose water to the aquifer under normal conditions of streamflow. The direction of seepage through the bed of these streams commonly is related to abrupt changes in the slope of the streambed (Figure 14A) or to meanders in the stream channel (Figure 14B). For example, a losing stream reach
usually is located at the downstream end of pools in pool and riffle streams (Figure 14A), or upstream from channel bends in meandering streams (Figure 14B). The subsurface zone where stream water flows through short segments of its adjacent bed and banks is referred to as the hyporheic zone. The size and geometry of hyporheic zones surrounding streams vary greatly in time and space. Because of mixing between ground water and surface water in the hyporheic zone, the chemical and biological character of the hyporheic zone may differ markedly from adjacent surface water and ground water.
Ground-water systems that discharge to streams can underlie extensive areas of the land surface (Figure 15). As a result, environmental conditions at the interface between ground water and surface water reflect changes in the broader landscape. For example, the types and numbers of organisms in a given reach of streambed result, in part, from interactions between water in the hyporheic zone and ground water from distant sources.
Unsaturatedzone
Saturated zone
Stream surface
Water table Flowing (gaining) stream
Location ofstart of flow
of stream
Unsaturatedzone
Saturated zone
Stream surface
Water table Flowing (gaining) stream
Location ofstart of flow
of stream
A
B
Streambed
Streambed
Streambed
Streambed
Figure 13. The location where peren-nial streamflow begins in a channel can vary depending on the distribution of recharge in headwaters areas. Following dry periods (A), the start of streamflow will move up-channel during wet periods as the ground-water system becomes more saturated (B).
El ro sera perdedor hasta que la recarga sea suficiente para que segenere flujo superficial pudiendo pasar a ser ganador.
Eduardo Cassiraga (UPV) Tema 5 22 / 43
-
Cambios en las relaciones aguas superficiales y aguas subterrneas Efecto de un cambio abrupto en la pendiente del cauce
Pendiente del cauce
La direccin del flujo infiltradoa travs del lecho semipermeablepuede verse afectada por cambiosbruscos en la pendiente del cau-ce y por los meandros que forma.Un cauce puede ser perdedoraguas arriba de un dique pero ga-nador aguas abajo.
17
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
Flow inhyporheic
zoneFlow in
hyporheiczone
Figure 14. Surface-water exchange with ground water in the hyporheic zone is associated with abrupt changes in streambed slope (A) and with stream meanders (B).
Figure 15. Streambeds and banks are unique environments because they are where ground water that drains much of the subsurface of landscapes interacts with surface water that drains much of the surface of landscapes.
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
Stream
Stream
Interface of local and regionalground-water flow systems,hyporheic zone, and stream
Direction ofground-water
flow
Dire
ction
of
grou
nd-w
ater
flow
Water table
Hy p o r h e i c z
o ne
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
Eduardo Cassiraga (UPV) Tema 5 23 / 43
-
Cambios en las relaciones aguas superficiales y aguas subterrneas Efecto de los meandros del cauce
Meandros del cauce
Un cauce puede ser ganadoraguas abajo de un meandro acausa de los flujos laterales que seoriginan.
17
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
A BMeandering
stream
Pool and rifflestream
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
Flow inhyporheic
zoneFlow in
hyporheiczone
Figure 14. Surface-water exchange with ground water in the hyporheic zone is associated with abrupt changes in streambed slope (A) and with stream meanders (B).
Figure 15. Streambeds and banks are unique environments because they are where ground water that drains much of the subsurface of landscapes interacts with surface water that drains much of the surface of landscapes.
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
@@@
Stream
Stream
Interface of local and regionalground-water flow systems,hyporheic zone, and stream
Direction ofground-water
flow
Dire
ction
of
grou
nd-w
ater
flow
Water table
Hy p o r h e i c z
o ne
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
Eduardo Cassiraga (UPV) Tema 5 24 / 43
-
Cambios en las relaciones aguas superficiales y aguas subterrneas Efectos del desarrollo agrcola
Desarrollo agrcola
La labranza de la tierra modifica las caractersticas de infiltracin y es-correnta de la superficie del terreno.Como consecuencia se ven afectadas la recarga de agua subterrnea, laentrega de agua y sedimentos a los cuerpos de aguas superficiales y laevapotranspiracin.Todos los procesos anteriores afectan la relacin entre aguas superfi-ciales y subterrneas.Para evitar los efectos negativos de la agricultura sobre los recursos h-dricos, los agricultores han modificado algunas de sus prcticas, porejemplo maximizando la retencin de agua en el suelo y minimizando laerosin del mismo.
Eduardo Cassiraga (UPV) Tema 5 25 / 43
-
Cambios en las relaciones aguas superficiales y aguas subterrneas Efectos del desarrollo agrcola
Sistemas de riego
Los sistemas de riego con agua superficial incluyen:Una compleja red de canales para conducir el agua hasta los cultivos.Un sistema de drenaje para evacuar el agua no utilizada por las plantas,que puede ser tan extenso y complejo como el de suministro.
Hay sistemas de riego que utilizan tambin agua subterrnea que seaplica directamente sobre los cultivos o que debe ser conducida a travsde un sistema de canales.
Eduardo Cassiraga (UPV) Tema 5 26 / 43
-
Cambios en las relaciones aguas superficiales y aguas subterrneas Efectos del desarrollo agrcola
Retornos de riego
Es comn que del agua regada entre el 75 al 85% se pierda en evapo-transpiracin y en retencin por parte de los cultivos.El resto se infiltra recargando los acuferos o vuelve a los cuerpos deagua superficial a travs de la red de drenaje.La cantidad de agua regada que recarga los acuferos es grande en re-lacin a la recarga por precipitacin.El resultado de esta recarga artificial puede ser una subida de los ni-veles piezomtricos, incluyendo la posibilidad del anegamiento de loscampos.Un sistema de drenaje que mantenga los niveles piezomtricos debajode la zona radicular es fundamental en algunos sistema de riego.La subida continua del nivel piezomtrico produce un aumento de la des-carga del acufero a los cuerpos de agua superficial.
Eduardo Cassiraga (UPV) Tema 5 27 / 43
-
Cambios en las relaciones aguas superficiales y aguas subterrneas Efectos del desarrollo agrcola
Retornos de riego
El problema surge cuando el ritmo de la recarga que producen los ex-cedentes de riego es superior a la descarga de los manantiales o dre-najes naturales o artificiales.La elevacin del nivel piezomtrico producida por los excedentes deriego es inevitable.Pueden aparecer nuevos manantiales o zonas de rezume.La evaporacin del agua de zonas encharcadas aumenta la salinidaddel suelo y produce el correspondiente deterioro agrcola de la zona.
Eduardo Cassiraga (UPV) Tema 5 28 / 43
-
Cambios en las relaciones aguas superficiales y aguas subterrneas Efectos del desarrollo agrcola
Retornos de riego
Llanura del ro Indus (Pakistn)
Eduardo Cassiraga (UPV) Tema 5 29 / 43
-
Cambios en las relaciones aguas superficiales y aguas subterrneas Efectos del desarrollo agrcola
Uso de agentes qumicos
La aplicacin de pesticidas y fertilizantes a las tierras de cultivo puedeprovocar la contaminacin de los recursos hdricos.Hay pesticidas poco solubles en agua que quedan ms bien retenidospor las partculas de suelo y no suelen contaminar el agua subterrnea.Otros, en cambio, se pueden detectar tanto en las aguas subterrneascomo en las superficiales.El amonio es el principal componente de fertilizantes y estircol, el cualse nitrifica aumentando la concentracin de nitratos en el agua.Que la contaminacin comience en las aguas superficiales o en las sub-terrneas no suele ser importante ya que una terminar contaminando ala otra dada su cercana interaccin.
Eduardo Cassiraga (UPV) Tema 5 30 / 43
-
Cambios en las relaciones aguas superficiales y aguas subterrneas Efectos del desarrollo urbano e industrial
Desarrollo urbano e industrial
Las fuentes puntuales de contaminacin de las aguas superficialespueden ser las descargas producidas a partir de plantas de tratamientode aguas residuales, instalaciones industriales y drenajes pluviales.El resultado es la introduccin en las corrientes superficiales de una va-riedad de contaminantes que pueden afectar la calidad del agua inclusoa grandes distancias de la fuente.Esta contaminacin puede afectar a las aguas subterrneas en caso deque se produzca la recarga del acufero por infiltracin, natural o indu-cida por extracciones, a travs de su lecho y/o sus riberas.Las fuentes puntuales de contaminacin del aguas subterrnea pue-den incluir fosas spticas, tanques de almacenamiento de fluidos, rellenossanitarios y lagunas industriales.Dependiendo del contacto con una masa de agua subterrnea y del tiem-po del vertido podra formarse un penacho de contaminacin en el sub-suelo que suele descargar en una corriente o cuerpo de agua superficial.
Eduardo Cassiraga (UPV) Tema 5 31 / 43
-
Cambios en las relaciones aguas superficiales y aguas subterrneas Efectos del drenaje de terrenos
Drenaje de terrenos
El drenaje de tierras con poca o nula pendiente mediante la construccinde zanjas abiertas o drenajes enterrados, suele ser un paso previo aldesarrollo agrcola o urbano.El drenaje de lagos y humedales afecta la distribucin de las zonas derecarga y descarga de aguas subterrneas afectando la biota y los pro-cesos qumicos y biolgicos subyacentes.As puede verse afectado el flujo base de los ros y los ecosistemas deribera.El drenaje tambin altera la capacidad de retencin de agua en las de-presiones de la topografa, as como las tasas de escorrenta superfi-cial de tierras con pendientes muy bajas (decrece la recarga subterrneay aumenta el flujo superficial).
Eduardo Cassiraga (UPV) Tema 5 32 / 43
-
Cambios en las relaciones aguas superficiales y aguas subterrneas Efectos de las modificaciones al valle de los ros
Construccin de diques
Los diques se construyen a lo largo de las riberas de los ros para prote-ger las tierras adyacentes de las inundaciones provocadas por ave-nidas.En general los diques suelen construirse para contener avenidas fre-cuentes (el ao por ejemplo) y son sobrepasados cuando la avenida espoco frecuente.La inundacin de tierras bajas es el ejemplo ms visible y extremo dela interaccin aguas subterrneas y aguas superficiales.Durante una avenida la recarga del agua subterrnea es continua y el nivelfretico podra alcanzar la superficie del terreno y saturar completamenteel acufero superficial.El drenaje del acufero puede tardar mucho tiempo despus de que lasaguas retroceden.
Eduardo Cassiraga (UPV) Tema 5 33 / 43
-
Cambios en las relaciones aguas superficiales y aguas subterrneas Efectos de las modificaciones al valle de los ros
Construccin de embalses
Todo embalse supone la modificacin del rgimen natural del ro cau-sando como norma general laminacin de crecidas.La disminucin de niveles aguas abajo de la presa provoca una dis-minucin de la recarga en los acuferos conectados hidrulicamente alro.Los materiales finos arrastrados durante una avenida se depositan enperiodos de aguas bajas aumentando la impermeabilidad del lecho delcauce.Las derivaciones de agua de los ros pueden tambin producir reduc-ciones importantes en los caudales aguas abajo del punto de derivacin.La gestin por parte del hombre de los flujos almacenados y libera-dos desde un embalse difieren considerablemente de los flujos naturales,lo que altera gravemente las condiciones ambientales en el ro aguas aba-jo.
Eduardo Cassiraga (UPV) Tema 5 34 / 43
-
Cambios en las relaciones aguas superficiales y aguas subterrneas Efectos de las modificaciones al valle de los ros
Construccin de embalses
Un embalse provoca una subidade los niveles piezomtricos enel entorno de la presa y hasta dis-tancias considerables.Este ascenso puede tener im-portantes consecuencias agr-colas, volviendo el terreno dema-siado hmedo para los cultivos oanegndolo.Tambin puede mejorar las condi-ciones de zonas que antes eransecas.Cerca de la presa, los embalses suelen perder agua que vuelve inmedia-tamente al ro como flujo base.En pocas en que los niveles embalsados son altos, el almacenamientode agua superficial en las riberas puede ser muy importante.
Eduardo Cassiraga (UPV) Tema 5 35 / 43
-
Cambios en las relaciones aguas superficiales y aguas subterrneas Efectos de las modificaciones al valle de los ros
Construccin de canales
Los canales no revestidospueden tener un efecto simi-lar a los embalses cuando lasuperficie del agua queda porencima del nivel piezomtrico.En caso contrario actan co-mo drenes haciendo descen-der los niveles pudiendo dejarsecos algunos pozos y perju-dicando los cultivos.
Eduardo Cassiraga (UPV) Tema 5 36 / 43
-
Cambios en las relaciones aguas superficiales y aguas subterrneas Efectos de las modificaciones al valle de los ros
Eliminacin de vegetacin natural
Se lleva a cabo para disponer de tierra para el desarrollo agrcola yurbano, lo que implica la tala de bosques y la eliminacin de vegetacinriberea y humedales.La deforestacin tiende a disminuir la evapotranspiracin, aumentar laescorrenta superficial y la erosin del suelo y a disminuir la infiltra-cin y el flujo base de los ros.Algunas de las funciones importantes de la vegetacin riberea y los hu-medales incluyen la preservacin de hbitat acutico, la proteccin dela tierra de la erosin, la mitigacin de las inundaciones, y el mante-nimiento de la calidad del agua.
Eduardo Cassiraga (UPV) Tema 5 37 / 43
-
Cambios en las relaciones aguas superficiales y aguas subterrneas Efectos de la accin de perforaciones
Bombeos en acuferos superficiales
Antes de los bombeos el acufe-ro est en equilibrio dinmico, larecarga es igual al flujo drenado alro.La situacin es la de ro ganador.Un bombeo Q1 capta parte del flu-jo que antes drenaba al ro y creauna divisoria de aguas subterr-neas.Un bombeo Q2 > Q1 invierte elsentido del flujo y hace que el rose transforme en perdedor.
15
Figure C1. In a schematic hydrologic setting where ground water discharges to a stream under natural conditions (A), placement of a well pumping at a rate (Q1) near the stream will intercept part of the ground water that would have discharged to the stream (B). If the well is pumped at an even greater rate (Q2), it can intercept additional water that would have discharged to the stream in the vicinity of the well and can draw water from the stream to the well (C).
Str
eamLand surface
Water table
Unconfined aquifer
Confining bed
Q1
Q2
Str
eamLand surface
Water table
Unconfined aquifer
Confining bed
Str
eamLand surface
Water table
Unconfined aquifer
Confining bed
Recharge area
A
B
C
Div
ide
15
Figure C1. In a schematic hydrologic setting where ground water discharges to a stream under natural conditions (A), placement of a well pumping at a rate (Q1) near the stream will intercept part of the ground water that would have discharged to the stream (B). If the well is pumped at an even greater rate (Q2), it can intercept additional water that would have discharged to the stream in the vicinity of the well and can draw water from the stream to the well (C).
Str
eamLand surface
Water table
Unconfined aquifer
Confining bed
Q1
Q2
Str
eamLand surface
Water table
Unconfined aquifer
Confining bed
Str
eamLand surface
Water table
Unconfined aquifer
Confining bed
Recharge area
A
B
C
Div
ide
15
Figure C1. In a schematic hydrologic setting where ground water discharges to a stream under natural conditions (A), placement of a well pumping at a rate (Q1) near the stream will intercept part of the ground water that would have discharged to the stream (B). If the well is pumped at an even greater rate (Q2), it can intercept additional water that would have discharged to the stream in the vicinity of the well and can draw water from the stream to the well (C).
Str
eamLand surface
Water table
Unconfined aquifer
Confining bed
Q1
Q2
Str
eamLand surface
Water table
Unconfined aquifer
Confining bed
Str
eamLand surface
Water table
Unconfined aquifer
Confining bed
Recharge area
A
B
C
Div
ide
Eduardo Cassiraga (UPV) Tema 5 38 / 43
-
Cambios en las relaciones aguas superficiales y aguas subterrneas Efectos de la accin de perforaciones
Recarga o descarga en sistemas ro-acufero
De especial importancia en acuferos aluviales conectados a ros.
Eduardo Cassiraga (UPV) Tema 5 39 / 43
-
Cambios en las relaciones aguas superficiales y aguas subterrneas Efectos de modificaciones en la atmsfera
Deposicin atmosfrica
La deposicin atmosfrica de sustancias qumicas, tales como sulfatosy nitratos, puede causar que algunos cuerpos de agua superficial seconviertan en cidos.El grado de susceptibilidad de un cuerpo de agua superficial a la llu-via cida est ligado, entre otras cosas, a la interaccin entre las aguassubterrneas y las aguas superficiales.Si un cuerpo de agua superficial recibi una importante descarga deagua subterrnea, la acidez del agua superficial puede ser en gran parteneutralizada.En caso contrario el cuerpo de agua superficial se transforma en muyvulnerable a la lluvia cida y podra desaparecer la vida acutica.
Eduardo Cassiraga (UPV) Tema 5 40 / 43
-
Cambios en las relaciones aguas superficiales y aguas subterrneas Efectos de modificaciones en la atmsfera
Calentamiento global
La concentracin de gases como el dixido de carbono y el metano,en la atmsfera tiene una efecto significativo sobre el balance de calorde la superficie de la Tierra y la atmsfera inferior.El calentamiento global, en caso de afectar los sistemas climticos, afec-tara al ciclo hidrolgico.Los acuferos superficiales son los ms sensibles a las variaciones cli-mticas estacionales y de largo plazo.Como resultado, la interaccin del agua subterrnea y de superficie tam-bin ser sensible a la variabilidad del clima o cambios en el clima.
Eduardo Cassiraga (UPV) Tema 5 41 / 43
-
Conclusiones
Conclusiones
La gestin de los recursos hdricos debe considerar a las aguas superfi-ciales y subterrneas como una nica entidad.Todos los cuerpos de agua superficial (ros, lagos, reservorios, humedalesy estuarios) interaccionan con las aguas subterrneas.Estas interacciones toman diferentes formas segn se gane o se pierdaagua o ambas cosas a la vez.Causas naturales y las actividades humanas afectan la distribucin,cantidad y calidad de los recursos hdricos.
Las aguas superficiales y las aguas subterrneas son dosmanifestaciones de un solo recurso integrado
Eduardo Cassiraga (UPV) Tema 5 42 / 43
-
Conclusiones
Bibliografa
Emilio Custodio y M. Ramn Llamas.Hidrologa Subterrnea.Ediciones Omega, S.A., segunda edicin, 1996.
Andrs Sahuquillo, Eduardo Cassiraga, Abel Solera y Jos Manuel Murillo.Modelos de uso conjunto de aguas superficiales y subterrneas.Instituto Geolgico y Minero de Espaa, 2010.
Thomas C. Winter, Judson W. Harvey, O. Lehn Franke y William M. Alley.Ground Water and Surface Water: A Single Resource.U.S. Geological Survey Circular 1139, Denver, Colorado, 1998.http://pubs.usgs.gov/circ/circ1139/
Eduardo Cassiraga (UPV) Tema 5 43 / 43
IntroduccinRelaciones entre ros y agua subterrneaRelaciones entre lagos y agua subterrneaRelaciones entre humedales y agua subterrneaCambios en las relaciones aguas superficiales y aguas subterrneasConclusiones
top related