Report on Surface Water & Groundwater Interaction

Ground Water & Surface Water Interaction by BAGARAGAZA M2014028 1 | P a g e

COLLEGE OF WATER CONSERVENCY AND HYDROPOWER

ENGINEERING

ACADEMIC YEAR 2014-2015,

MODULUS: NUMERICAL SIMULATION OF GROUNDWATER

STUDENT ID: M2014028

STUDENT NAME: BAGARAGAZA ROMUALD

MAJOR: WATER CONSERVANCY AND HYDROPOWER ENGINEERING

Lecturer Module Leader: Dr. Longcang SHU, Prof. of Hydrogeology

Topic on:

Improved ground-water and surface-water interactions, which include both

inflows and outflows from groundwater systems.

COLLEGE OF INTERNATIONAL STUDENTS


TABLE OF CONTENTS 1. WHAT IS WATER INTERACTION ................................................................................................................. 3

2. INTRODUCTION ......................................................................................................................................... 3

3. GROUND /SURFACE WATER RESOURCE ................................................................................................... 3

4. WHAT IS WATERCYCLE AND INTERACTIONS OF GROUND WATER AND SURFACE WATER ...................... 4

4.2 Typical example of movement of water in the atmosphere and on the land surface ....................... 6

4.3 Effect of transpiration on ground water ............................................................................................. 9

5. TERMINOLOGY USED IN GROUND WATER AND STREAMS ..................................................................... 10

5.1 Stream Gaining .................................................................................................................................. 10

5.2 Stream losing .................................................................................................................................... 10

5.3 Losing disconnected stream ............................................................................................................. 11

6. INTERACTION OF GROUND WATER AND LAKES ..................................................................................... 12

6.1 Groundwater inflow (gaining lake) ................................................................................................... 12

6.2 Seepage loss to the saturated zone (losing lake) .............................................................................. 13

6.3 Groundwater inflow in certain parts and seepage loss from others (flow-through lake) ................ 13

7. INTERACTION OF GROUND WATER AND WETLANDS ............................................................................. 14

7.1 CONCLUSION ON WETLAND ............................................................................................................. 15

8. MEASURING OF GROUNDWATER ........................................................................................................... 16

9. CONCLUSION AND RECOMMENDATION ................................................................................................ 17

9.1 CONCLUSION ..................................................................................................................................... 17

9.2 RECOMMENDATION ......................................................................................................................... 17

REFERENCES ................................................................................................................................................ 18


1. WHAT IS WATER INTERACTION

Groundwater and surface water are essentially one resource, physically connected

by the water cycle. Groundwater and surface water interactions are controlled by their hydraulic connection.

2. INTRODUCTION

Groundwater and surface water are two interconnected components of one

single resource and impacts on either of these components will inevitably affect

the quantity or quality of the other (Winter et al. 1999). Although early

hydrological research had already emphasized these linkages between

Groundwater and surface water, these resources have long been perceived and

managed as two separate entities. However, with growing demands on water

resources and increasing uncertainties in water supply associated with climate

change the awareness for the need to manage Groundwater and surface water as

a single resource has steadily grown and also found its way into new legal

frameworks to regulate the sustainable use of water resources in many countries.

It is clear that an improved multidisciplinary understanding of the processes and

dynamics of GWSW interactions is an important prerequisite to tackle these new

challenges. This Special Issue addresses some of the scientic challenges in

characterizing, quantifying and modelling GWSW interactions and outlines new

methods and models to improve our understanding of processes and dynamics at

the GWSW interface.

3. GROUND /SURFACE WATER RESOURCE

Issues related to water supply, water quality, and degradation of aquatic

environments are reported on frequently. The interaction of ground water and

surface water has been shown to be a significant concern in many of these issues.

For example, contaminated aquifers that discharge to streams can result in long-

term contamination of surface water; conversely, streams can be a major source of

contamination to aquifers. Surface water commonly is hydraulically connected to

ground water, but the interactions are difficult to observe and measure and


commonly have been ignored in water-management considerations and policies.

Many natural processes and human activities affect the interactions of ground

water and surface water. The purpose of this report is to present our current

understanding of these processes and activities as well as limitations in our

knowledge and ability to characterize them.

4. WHAT IS WATERCYCLE AND INTERACTIONS OF GROUND

WATER AND SURFACE WATER

The watercycle sounds like it is describing how water moves above, on, and below

the surface of the Earth continuously. The water on the Earth's surface occurs as

streams, lakes, and wetlands, as well as bays and oceans. Surface water also

includes the solid forms of water-- snow and ice. The water below the surface of

the Earth primarily is ground water, but it also includes soil water.

The watercycle is clarified in the below diagram that shows only major transfers of

water between continents and oceans. However, to understand hydrologic

processes and managing water resources, the watercycle needs to be viewed at a

wide range of scales and as having a great deal of variability in time and space.

Precipitation, which is the source of virtually all freshwater in the watercycle, falls

nearly everywhere, but its distribution, is highly variable. Similarly, evaporation

and transpiration return water to the atmosphere nearly everywhere, but

evaporation and transpiration rates vary considerably according to climatic

conditions. As a result, much of the precipitation never reaches the oceans as

surface and subsurface runoff before the water is returned to the atmosphere.

Figure 1. watercycle


5. FLOW DIAGRAM OF SURFACE WATER AGAINST GROUNDWATER

To present the concepts and many facets of the interaction of ground water and

surface water in a unified way, a conceptual landscape is used below. The

conceptual landscape shows in a very general and simplified way the interaction of

ground water with all types of surface water, such as streams, lakes, and wetlands,

in many different terrains from the mountains to the oceans. The intent of Fig.2 is

to emphasize that ground water and surface water interact at many places

throughout the landscape.

Fig2. Ground water and surface water interact throughout all landscapes from the

mountains areas.


4.2 Typical example of movement of water in the atmosphere and on the

land surface

Movement of water in the atmosphere and on the land surface is relatively easy to

visualize, but the movement of ground water is not. Concepts related to ground

water and the movement of ground water is introduced in Box A. As illustrated in

Figure 3, ground water moves along flow paths of varying lengths from areas of

recharge to areas of discharge. The generalized flow paths in Fig. 3 start at the

water table, continue through the ground-water system, and terminate at the stream

or at the pumped well. Source of water to the water table (ground-water recharge)

is infiltration of precipitation through the unsaturated zone. In the uppermost,

unconfined aquifer, flow paths near the stream can be tens to hundreds of feet in

length and have corresponding travel times of days to a few years. The longest and

deepest flow paths in Fig. 3 may be thousands of feet to tens of miles in length, and

travel times may range from decades to millennia. In general, shallow ground

water is more susceptible to contamination from human sources and activities

because of its close proximity to the land surface. Therefore, shallow, local

patterns of ground-water flow near surface water are emphasized in this Circular.

Small-scale geologic features in beds of surface-water bodies affect seepage

patterns at scales are too small. For example, the size, shape, and orientation of the

sediment grains in surface-water beds affect seepage patterns. If a surface-water

bed consists of one sediment type, such as sand, inflow seepage is greatest at the

shoreline, and it decreases in a nonlinear pattern away from the shoreline.


Fig.3. Ground-water flow paths vary greatly in length, depth, and traveltime from

points of recharge to points of discharge in the ground-water system

Fig. 4. Ground-water seepage into surface water usually is greatest near shore.


In flow diagrams such as that shown here, the quantity of discharge are equal

between any two flow lines; therefore, the closer flow lines indicate greater

discharge per unit of bottom area.

Fig. 5. Subaqueous springs can result from preferred paths of ground-water flow

through highly permeable sediments.

The fluctuation of meteorological conditions also strongly affects seepage patterns

in surface-water beds, especially near the shoreline. The water table commonly

intersects land surface at the shoreline, resulting in no unsaturated zone at this

point. Infiltrating precipitation passes rapidly through a thin unsaturated zone

adjacent to the shoreline, which causes water-table mounds to form quickly

adjacent to the surface water (Fig.6). This process, termed focused recharge, can

result in increased ground-water inflow to surface-water bodies, or it can cause

inflow to surface-water bodies that normally have seepage to ground water.

Fig6. Ground-water recharge surface-water bodies and beneath depressions in the

land surface.


4.3 Effect of transpiration on ground water

Transpiration by near shore plants has the opposite effect of focused recharge.

Again, because the water table is near land surface at edges of surface-water

bodies, plant roots can penetrate into the saturated zone, allowing the plants to

transpire water directly from the ground-water system form Fig7.Transpiration of

ground water commonly results in a drawdown of the water table much like the

effect of a pumped well. This highly variable daily and seasonal transpiration of

ground water may significantly reduce ground-water discharge to a surface-water

body or even cause movement of surface water into the subsurface. Ground water

moves into the surface water during the night, and surface water moves into

shallow ground water during the day.

Fig7. Cone of depression caused by plant root transpiration

The depth to the water table is small adjacent to surface-water bodies, transpiration

directly from ground water can cause cones of depression similar to those caused

by pumping wells. This sometimes draws water directly from the surface water

into the subsurface.

These periodic changes in the direction of flow also take place on longer time

scales: focused recharge from precipitation predominates during wet periods and

drawdown by transpiration predominates during dry periods. As a result, the two

processes, together with the geologic controls on seepage distribution, can cause

flow conditions at the edges of surface-water bodies to be extremely variable.

Transpiration


5. TERMINOLOGY USED IN GROUND WATER AND STREAMS

When the streams interact with ground water the interaction takes place in three

basic ways: streams gaining and stream losing.

5.1 Stream Gaining

A stream that receives water emerging from a submerged spring or other

groundwater seepage which adds to its overall flow or when stream receive water

from the ground-water discharge.

Fig8. Gaining streams receive water from the ground-water system

5.2 Stream losing

Stream losing or disappearing stream is a stream or river that loses water as it

flows downstream. The water infiltrates into the ground recharging the

local groundwater, because the water table is below the bottom of the stream

channel.

A. Stream Gaining

B. Stream losing


Fig 9. Losing streams lose water to the ground-water system

5.3 Losing disconnected stream

Losing disconnected stream is a special type of losing stream. In this case, the

water table is actually below the bottom of the stream bed.(

http://www.gg.uwyo.edu) Thus, water percolations or infiltrates down through the

unsaturated zone to final enter the saturated zone. In this case, the stream surface is

not coincident with the water table and the water table never lies above the ground

surface. Disconnected streams are common in arid region

Fig10. Disconnected streams

In some environments, stream flow 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. As long as the stream has water flowing in it, the water table below the

stream will bow upward. If a disconnect stream dries up, water is no longer being

supplied to the saturated zone. Sometime after the stream dries up, the water in the

water table bulge will flow away and the water table will flatten beneath the

stream.

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 stream banks. As long as the rise in stage does not

overtop the stream banks, most of the volume of stream water that enters the

stream banks 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 supplement stream flows.


If a stream is separated from the groundwater table by an unsaturated zone, it is a

hydraulically "disconnected" system. In disconnected systems, although

groundwater pumping does not affect streams, streams do affect groundwater

through streambed seepage that recharges the groundwater system.

Groundwater systems are often disconnected from the streams in arid regions and

in regions where groundwater pumping has significantly lowered groundwater

levels.

6. INTERACTION OF GROUND WATER AND LAKES

Lakes interact with ground water in three basic ways: some receive ground-water

their entire bed; some have seepage 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.(Winter, Harvey, Franke,

& Alley, Denver, Colorado 1998) some lake doesnt interact with the ground water

With respect to lakes, groundwater interacts with these features in three ways:

6.1 Groundwater inflow (gaining lake)

http://albertawater.com/groundwater Lakes can receive ground-water inflow

Here lake gains groundwater on the both sides and even at

the bottom. Means that the increase of water in lake will

depends on groundwater influent. Versus the decrease.


6.2 Seepage loss to the saturated zone (losing lake)

http://albertawater.com/groundwater lake lose water as seepage to ground water

6.3 Groundwater inflow in certain parts and seepage loss from others

(flow-through lake)

The fig. below shows us how the decrease of water level,

from lake will differ on the bed bottom of the lake

constituent. Lake is losing water to recharge groundwater

aquifer

lake gains groundwater on the one sides but lose water on the other

sides , Means that the increase of water in lake will depends on how

much groundwater influent compare to effluent.


http://albertawater.com/groundwater lake gain lose water as seepage to ground water

Although the basic interactions are the same for lakes as they are for streams, the

interactions differ in several ways. The water level of natural uncontrolled lakes

generally does not change as rapidly as the water level of streams.

Evaporation has the greatest natural effect on lake levels but water withdrawals,

either through direct off-take of pumping of shallow groundwater nearby, can also

effect a change in lake water levels by directly lowering levels or encouraging

enhancing seepage loss.

7. INTERACTION OF GROUND WATER AND WETLANDS

Wetlands are present in climates and landscapes that cause ground water to

discharge to land surface or that prevent rapid drainage of water from the land

surface. Similar to streams and lakes, wetlands can receive ground-water inflow,

recharge ground water, or do both. Those wetlands that occupy depressions in the

land surface have interactions with ground water similar to lakes and

streams.(Winter et al., Denver, Colorado 1998).

The wetland is not always located at the lowest point. Sometimes, in areas of steep land slopes, the water table intersects the land surface, resulting in ground-water

discharge directly to the land surface.(Winter et al., Denver, Colorado 1998) so

normally the continuous movement will facilitate plant growth.

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(Schelesinger, 1991).Wetland

areas can also gain or lose water much like lakes. In areas of steep terrain, the

water table sometimes intersects the land surface, resulting in groundwater

discharge directly to the land surface.


Schematic diagram of the water balance components of wetland.

wetland refers to a topographic depression having saturated or nearly saturated soil most of the year, which includes the riparian zone occupied by dense including

phreatophytes such as sedges (Carex sp.), willow (Salix sp.) and poplar(van der

Kamp, 2008)

Generally, wetlands are lands where saturation with water is the dominant factor

determining the nature of soil development and the types of plant and animal

communities living in the soil and on its surface (Cowardin, December 1979).

Wetlands can receive groundwater inflow, recharge the groundwater system, or do

both. Wetlands that occupy depressions in the land surface have interactions with

groundwater similar to lakes and streams. Unlike lakes and streams, wetlands do

not always occupy low points and depressions in the landscape. They also can be

present on slopes (such as fens) or even on drainage divides (such as some types of

bogs). The different types of wetlands include fens, bogs and swamps/marshes

7.1 CONCLUSION ON WETLAND

As conclusion on wetlands exist in areas where groundwater discharges to the land

surface or on landscapes that prevent rapid drainage of water from the surface in

conducting wetland hydrology studies.

Recognition of such differences is important because wetland plant communities

are commonly influenced by water chemistry as well as saturation levels.

Therefore, the multidisciplinary approach yields a more comprehensive

understanding of the hydrology of wetlands.(Shedlock, Wilcox, Thompson, &

Cohen, 1-1-1993). If the discharge is a sustained flow, it is referred to as a spring.


Conversely, if the rate of evaporation is nearly equal to the rate of delivery then it

may only manifest as a wet patch, or seep. The constant source of water to these

features supports the growth of wetland vegetation.

8. MEASURING OF GROUNDWATER

Ground water scientists have conducted and continue to conduct extensive research

in the development of technical tools to measure and predict the presence of

surface water/ ground water. While progress has been made, the methods of

measurement are extremely complex, require extensive technical knowledge, and

are resource intensive.

Various probes may be used to measure changes within the channel, which may

indicate the points of surface water/ ground water interaction. Temperature probes

may be used to determine change in temperature, which indicate influence of

ground water on surface water. Hyporheic probes may be used to measure

interstitial flow rates and change in gradient, and a piezometer may be used to

measure change in hydraulic head, which indicate the potential for and surface

water to interact.(GARDNER, 1998).


9. CONCLUSION AND RECOMMENDATION

9.1 CONCLUSION

In this work we tried demonstrate and to illustrate how ground water flows within

a riverside system, not only that and how surface water recharges it, the ecological

importance of the surface water and ground water interaction is within the

environment. We also discussed the problems that arise when we fail to

acknowledge the interconnectedness of surface and ground water. Measurement

and interpretation of interaction areas are complex. However, with attention and

perseverance, developing our understanding of surface water and ground water

interactions has the ability to enhance our efforts to protect watersheds and

improve conditions for the lives reliant upon healthy watersheds.

9.2 RECOMMENDATION

The course NUMERICAL SIMULATION OF GROUNDWATER was well

conducted and we gain lots. In all engineering field we know that the theoretical

knowledge mast be equally to the practical knowledge, thats why the following are my recommendation on the coming years.

I wish that if possible for next years to prepare some laboratories for your students, for example; the measurement of soil permeability , transmissivity,

etc.

The second one I would like also to point practical issues, if possible to drill a water well here at hohai so that it will be used as demonstration for

students, especially in case of determining groundwater quantity through a

well.

To prepare a practice on how to measure the groundwater depth from the earth surface.


REFERENCES

1. http://www.gg.uwyo.edu/content/laboratory/groundwater/gw-streams/lose-

streams/disconnected.asp?callNumber=34981&SubcallNumber=0&color=&

unit=copper last seen 2015-05-10.

2. GARDNER, K. M. (1998).

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Report on Surface Water & Groundwater Interaction