Ekologi Sungai Fix

8/7/2019 Ekologi Sungai Fix

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EKOLOGI SUNGAI

MK. EKOLOGI LINGKUNGAN MA 2010

KEY CONCEPTS

1. ASPEK FISIK KIMIA SUNGAI

2. ASPEK BIOLOGI SUNGAI

3. PROSES EKOSISTEM SUNGAI

These elements are not independent of

each other, but rather continuouslyinteract in a myriad of relationships. For

that reason, altering a singlecomponent-manipulating flow through

the construction of a dam, for example-can affect all other components in

unpredictable and often deleteriousways.

Intro: Sungai Stream of Life

Many of the world's great cities developed the banks of a great river.Rivers have been the lifeblood of civilization, the staff of life itself.

River provide valuable goods and services to humans and to the naturalsystems on which we depend.

Throughout our history, natural streams have provided:

Clean water

Habitat for plants, wildlife, and fish-many of direct benefit to humans

Storage of floodwaters in the floodplain and wetlands, reducing themagnitude and destructiveness of flooding

Transportation, from light canoes to fleets of barges

Power for mills and power plants

Removal of effluent, heat, and other waste

Beauty, spiritual significance, and even national identity

MENGAPA PENTING?

Water is vital to all life on Earth uniquesubstance its thermal-density relationship solid,liquid, and gas. The high specific heat of liquid water to provide a much more stable environment thanis found in terrestrial environments. These propertiesand many other characteristics of the water moleculeessentially control the chemical and biologicaldynamics of rivers (Wetzel, 2001).

Understanding how rivers run enables us to betterrealize their value to us-socially, ecologically, andeconomically. We are better prepared to recognizethe tradeoffs we make when we manipulate a riverfor our own purposes-by building a dam for powergeneration, or dredging for shipping, or withdrawing

water for irrigation.

LANJUTAN

Understanding how rivers run also

enables us to restore rivers toecological health-as sources of drinkingwater, as fisheries, as habitats for avariety of life-as sustainableecosystems.

restoration without knowledge of how ariver works most often led to failure.

A deeper understanding of river systems can guide individual

choice and action. An informed citizenry can make a big

difference through their votes, voices, and vocations.

FLOW/HYDROLOGY

hydrologydistribution and movement of water through the stream andits floodplain and tributaries.

Water is vital to life in the stream and the nearby environment. Itsmovement provides the energy to shape the stream and its surroundinglandscape. Its unique physical properties-it floats when it turns to ice andhas an unusual ability to retain heat.

The hydrology of a river system appearance and behavior of thestream and its ability to support life and other processes and uses,including those that humans depend on.

There are four variables or dimensions of hydrology:

Longitudinal, the movement of water from headwaters downstream to the m outh.

Lateral, the ebb and flow of water between the main channel and thefloodplain.

Vertical, the flux of water underground.

Chronological, the flow over time.
http://files.dnr.state.mn.us/assistance/backyard/healthyrivers/course/600/r101_00.htmhttp://files.dnr.state.mn.us/assistance/backyard/healthyrivers/course/600/r101_00.htm


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SIKLUS HIDROLOGI

Precipitation through the hydrologic cyclefeeds the world's streams. Waterevaporates from the world's oceans (andto a lesser extent, lakes and streams) and

via transpiration of plants. It falls from theatmosphere as rain or snow. Flowing overground as runoff or underground asgroundwater, water finds its way to astream and then eventually to the sea.

Why do rivers continue to flow, even whenlittle or no rain has fallen? Much of thewater feeding a stream runs slowlyunderground through shallow aquifers.These sediments are saturated like naturalsponges and respond slowly to rainfall anddrought.

Evaporasi

Evapotranspirasi

Sebagai Ilustrasi8Bisri, 2009

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SIKLUS HIDROLOGI

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SIKLUS HIDROLOGI

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Hujan

SIKLUS HIDROLOGI

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12Peresapan

Infiltrasi

Airtanah(Bebas)

Airtanah(Tertekan)

Mata Air

Lapisan Kedap Air

Dataran Banjir

Lereng Tidak Stabil

Muka Airtanah(Bebas)

Evaporasi

Evapotranspirasi

Hujan

SIKLUS HIDROLOGI

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DAS

A stream's watershed(also

called its basin or catchment)

is the land area that drainsinto that particular stream.

As one stream joins another,

the watershed jumps in sizeas two watersheds are

joined. Thus a watershedgrows to great proportions.

STREAM ORDERS

Most streams begin as springs ofgroundwater. Some flow from lakes withoutan inlet. These fledgling streams arelabeled first order. When a first order

stream meets another first order streamsecond order stream.

The second order stream picks upadditional first order streams, but remainssecond order. Only when two second orderstreams meet is the result a third orderstream.

As you might expect, there are vastly moresmall streams than large ones. In fact, thereare about four (4.4) times as many streamsof one order than of the next higher order.

FACTORS OF fLOWS

Several factors affect the timing, rate, and volume of flowthrough a stream system:

Climate

Precipitation

Evaporation

Transpiration

Vegetation

Geology

Land use

Soil

SEASONAL VARIABILITY

The amount of precipitation the volume of flow

through a stream over time seasonal pattern of

streamflow.

These anticipated changes in streamflow throughout

the year seasonal variability

A hydrograph is a picture that depicts the seasonal

or intra-annual variability of streamflow.

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Debit(m3/dt)

Bulan

Gambar Debit Aliran Sungai Rata-rata (m3/detik)

DAS Welang

Flow Pattern

Each stream has a typical pattern of flows.Streams with significantly different

watershed characteristics (such as a streamwith a high groundwater content comparedto a stream fed almost entirely by runoff)different hydrographs.

Seasonal variability is natural andnecessary for the functioning of the riverecosystem. River organisms have evo lvedunder a regime of high flows and lowflows. Bank-high flows form and maintainthe shape of the river channel; flushsediment from feeding and spawning areas;signal migration for certain species; andallow passage upstream.

TOPOGRAFI

Topography of the watershed is another factor

affecting flow into a river system.

Steep hills drain quickly; level land bogs,

wetlands, or lakes retains water and flow more

slowly to streams.

Bare bedrock and impermeable clay drain more

quickly than porous soils, such as sand. Porous soils

and fractured bedrock allow runoff to enter the

groundwater supply


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VEGETASI

Plant cover also affects the rate andamount of flow into streams.

Runoff from bedrock or barren desertsoils will be quicker than the flowof water over grassy plains or overforested land carpeted withwoodland plants and organic duff.

Organic material absorbs water andimpedes its flow. Plants divert waterby taking it up through their roots andstoring it briefly before it is lostthrough transpiration.

LAND USE

Human land use has greatly affected the flow of water into rivers andstreams.

Clear-cutting of forests,

plowing land for agriculture, paving land for roads and parking lots,

compacting land through heavy use, and

draining wetlands-all have increased the speed with which water runs off theland into nearly streams and lakes. In most cases, erosion and movement of soilhave also increased.

By speeding the flow of water into rivers, these land use changes alter thehydrology of a stream, causing streamflows to rise faster and peak athigher levels. The higher flows carry greater amounts of sediment. Assurface runoff increases (and the contribution of groundwaterproportionately decreases) stream temperatures generally rise. Increasedtemperature, turbidity, and current velocity affect stream life, usually for theworse.

Hutan Gundul

Lahan Terbuka

Pertanian pada lahan miring

Air sungai keruh akibat erosi

Perbukitan gundul di Pujon Malang

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PENGEMBANGAN DAS(TIDAK TERKENDALI)

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PENGEMBANGAN DAS

(TIDAK TERKENDALI)

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PENGEMBANGAN DAS

(TIDAK TERKENDALI)

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Peresapan air berkurang Muka airtanah turun, Mata Air kering Terjadi intrusi air laut

Banjir bandang Pendangkalan sungai dan muara Daerah banjir meluas

Erositinggi

Longsor

Pada musim kemarauair sungai nyaris kering


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BANKFULL FLOWS STREAM CLASSIFICATIONS

HABITAT

Stream's hydrodynamic forces

rich diversity of habitats for

aquatic life. This diversity results

from variation in stream depth,

width, water velocity, and substrate

throughout the channel. Diverse

habitats support a high degree of

biological diversity.

4. KUALITAS AIR

Because water is vital to life, it is accurate to say thatpoor water quality equals a poorer quality of life.

Water quality in a stream can be assessed usingbiological indicators. Water quality is also determinedby measuring a variety of physical and chemicalproperties, including: Temperature

Dissolved oxygen

Alkalinity and pH

Nutrients

Sediment and turbidity Contaminants

TEMPERATURE

Certain physical processes are influenced by

temperature. The most obvious is the formationof ice on the surface, along the banks, andeven on the bed of a stream. Other effects aresubtler.

Because water becomes more viscous as it getscolder, cold water can hold more sediment thanwarm water can. Consequently, cold water hasgreater erosive power. Cold-water releasesfrom a newly constructed dam can beexpected to cause new erosion to the streamchannel because (1) cold water is more erosivethan the warm water it replaces, and (2) thereservoir traps sediment, leaving the releasedwater with greater capacity to pick up newsediment.

Temperature governs other basic properties ofwater, such as surface tension and density temperature influences the rate of evaporation,infiltration, and percolation through sediments.Temperature also governs the type and rates ofchemical reactions in water.

Temperature influences stream lifeperiods ofmigration, growth, and dormancy. It governs therate of metabolism, chemical processes, anddetermines when habitats are suitable for specificlife stages of species.

Water temperature affects the type and abundanceof algae. At the same nutrient level, green algaetend to dominate at higher temperatures whilediatoms decline. At the highest temperatures, blue-green algae thrive and often develop into heavyoutbreaks or "blooms"


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DO

Each natural stream has itscharacteristic regime ofdissolved oxygen, relatedlargely to temperature andthe breakdown of organicmaterial in the water.

Water temperature stronglyinfluences the amount ofdissolved oxygen in a streambecause the ability of waterto hold DO decreases astemperature increases

DO: CONS

Many human activities can cause aharmful decline in DO levels. Manurespills from feedlots or routine runofffrom farmland can vastly increase the

biological oxygen demand (BOD) of astream.

Runoff from city streets and residentiallawns, effluent of partially treatedhuman sewage, and discharge ofoxidizing industrial chemicals can alsoincrease BOD in rivers and streams.

Human activities that add nu trients tothe stream can greatly increase algalabundance. At night, algae no longerproduce but only consume oxygen.Dissolved oxygen levels can dip duringthe night below life-sustainingthresholds.

NUTRIENT

Nutrients, principally n itrogen and phosphorus, are ot her important

components of water chemistry.

TOXIN

Toxins include a range of poisonous or otherwise harmful substances,such as heavy metals, road salts, and pesticides.

Heavy metals, including mercury, cadmium, and lead, come from avariety of sources, such as industrial processes, trash incineration,automobiles, and emissions from power plants. Concentrations ofmany of these metals tend to increase as rivers pass through largecities and collect urban runoff and industrial point sources. But some,such as mercury, are also dispersed in the atmosphere and reachstreams through precipitation and runoff.

Many metals are toxic, even at very low concentrations. One of thegreatest known threats to human health is the concentration ofmercury (from mines, power plants, and paper mills) in muscle tissueof fish. Overexposure to mercury damages the brain, nervoussystem, kidneys, and lungs.

TOX: PESTICIDES

Pesticides include many kinds of chemical poisons andbiological agents used to control insects and weeds.

Pesticides have been a fundamental cog in the so-called Green Revolution that has increased cropyields since the 1950s. Though the number ofpesticides is vast, a few commonly u sed pesticidesaccount for the overwhelming majority of pesticides inthe environment.

Pesticides enter streams through polluted runoff,primarily from lawns and farmfields. They may alsoenter groundwater.

Pesticides have undergone steady development.Long-lived chlorinated organic compounds such asDDT have given way to new pesticides that aregenerally less persistent in the environment. Theecological effects of pesticides depend on manyfactors-toxicity, persistence, their byproducts ofdegradation, and their chemical behavior

LIFE

Rivers are indeed ribbons of life-complex,

productive, valuable communities of terrestrial

and aquatic plants and animals joined and

sustained by the many forces, interactions, and

pathways that make up a living stream.


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TERRESTERIAL PLANTS

Terrestrial plants along thestream, in its floodplain, and in

its valley are vital to thecharacter of the stream. Thepattern of vegetation along astream corridor will depend onclimate; disturbance such asflood, erosion, and fire;formation of floodplains; soiltype; and soil moisture.

RCC

plant and animal communitiesgradually change fromheadwaters to lower stretchesof streams.

The River Continuum Conceptdescribes the evolving patternsand interactions of energyinputs, physical environment,and biological communities asone moves from the source of astream toward its mouth

Generally, as one movesdownstream, the physicalenvironment and the plant andanimal communities that livethere increase in complexity

Ecological Process

Tumbuhan dan komunitas hewan telah berevolusi

dengan aliran, bentuk, koneksi, dan kualitas sistem

sungai di mana mereka tinggal. Sama seperti binatang

yang dipengaruhi oleh sungai, sungai juga dapat

dipengaruhi oleh hewan.

But the most influential animal that impacts streams isthe mammal Homo sapien sapiens . Humans are changing

the flow, shape, connections, and water quality of most

river systems, putting many plant and animalcommunities at great risk, and ultimately, us.

TERIMAKASIH

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Ekologi Sungai Fix

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