Streams and Rivers Streams A body of water

Streams and Rivers

Streams • A body of water with a current, and is smaller than a river • When joined, they form a bigger body of water either flowing or nonflowing water ecosystem. ▫ Lakes ▫ Ponds ▫ Inland wetlands – Rivers

Rivers • A body of water with a current and is larger than streams • The volume of water it carries is larger than the volume of water streams carry.

TERMS • Tributary • Watershed

Watershed • A watershed is the area of land where all of the water that is under it or drains off of it goes into the same place.

Watershed • Closed watershed ▫ empties into an inland body of water • Open watershed ▫ empties to the ocean • Multiple open watershed ▫ empties into the ocean through more than one mouth

Tributary • A tributary is a stream that flows into a larger stream or other bodies of water. • A contributory stream, or a stream which does not reach the sea but joins another river.

Rivers • The rivers are classified on the basis of the sediments it carries

Course of a River

Upper Course • Where the river begins • Many smaller streams join up to form larger streams • Several streams join up to form a river • Narrow and v-shaped river channel • Steep gradient

Middle Course • River starts to meander • More tributaries joining the river • Wider river channel than upper course • Gentler gradient as compared to upper course

Lower Course • Meanders are common • Distributaries distribute water away from the river to the sea • Wider river channel than middle course • High volume of water • Gentle gradient

Three main types of rivers • Youthful River - A youthful river has a steep gradient and very few tributaries. A youthful river is bound to flow quickly and swiftly. Mature River - A mature river is less steep and flows slowly compared to the youthful river. There are many tributaries that feed a mature river. The sediment deposit is also less. Old River - An old river has a low gradient and is depended on flood plains is known as old river.

Youthful Mature Old

Where are rivers located? Rivers are found anywhere in the world except in antarctica.

Top 3 longest rivers in the world • The longest river in the world is the Nile River (4, 157 miles long); it is located in northeastern Africa, and flows into the Mediterranean Sea.

• The second-longest river is the Amazon River (3, 915 miles long); it is located in northeastern South America, and flows into the Atlantic Ocean.

• The third-longest river is the Chang (Yangtse) River (3, 434 miles long); it flows across southcentral China into the East China Sea.

AMAZON - 12 th order stream, the - highest rank possible in the stream order system.

STREAMS

Three main types of streams: • Ephemeral streams ▫ regularly exist for short periods of time, usually during a rainy period. • Intermittent streams ▫ flow at different times of the year, or seasonally, when there is enough water from either rainfall, springs, or other surface sources. • Perennial streams ▫ streams that flow year-round.

The tributaries (streams) are identified by their stream order, denoted by its position in the system. Stream Order Characteristics First Order not connected to any other tributaries Second Order connected to one other stream/tributary Third Order joining of two second order streams

First-order stream

Second-order stream

Third order stream

ABIOTIC FACTORS • Precipitation ▫ formation of streams and rivers. ▫ Amount of precipitation determines which type • Current ▫ determine the substrate at the bottom • Landscape ▫ determine direction • Temperature ▫ Affects the organisms ▫ Reproduction �Different organisms reproduce at different temperatures

ABIOTIC FACTORS • Trout will not reproduce below 3 degrees and ideally between 5 and 16 degrees.

ABIOTIC FACTORS • Carp reproduce best above 20 degrees.

Biotic Factors

Plant adaptations • Air Spaces ▫ decrease density and increase buoyancy • Broad leaves ▫ spread their weight more evenly across the water surface allowing them to float

• Waxy cuticle ▫ allow water to run off the surface preventing the weight of the water from dragging the leaves under the surface • Strong holdfast ▫ Used by water mosses (Fontinalis) and heavily branched filamentous algae to cling on to rocks

• Cushion like colonies or closely appressed sheets that are covered with a slippery gelatinous coating

Animal adaptations • Streamlined form ▫ Offers less resistance to water current • Extremely flattened and broad bodies, flat limbs ▫ Allow the current to flow over the bodies of some larval forms Brook trout Pearl dace

• Snails and planarians ▫ Attached themselves to sticky under surfaces allowing them to cling tightly and move about on stones and rubble in the current.

Four major groups of inhabitants (according to feeding habits) • Shredders ▫ Feed on coarse particulate organic matter (CPOM) �CPOM – mostly leaves that fall into the stream and are softened by water and colonized by bacteria and fungi. Casemaker caddisfly

• Filtering and gathering collectors ▫ Feed on the fine particulate organic matter (FPOM) �FPOM – leaves that are broken down by the shredders, partially decomposed by microbes, and invertebrate feces that drift downstream and settle on the stream bottom. Freshwater mussels Gougers Invertebrates that burrow into water-logged limbs and trunks of fallen trees

• Grazers ▫ Another group that feed on the algal coating of stones and rubble Water penny

Human impact • Draining of rivers and streams The now dry Colorado River delta branches into the Baja/Sonoran desert just five miles north of the Sea of Cortez, Mexico. Photo by Peter Mc. Bride

• Water diversion and regulation of flows due to dams. ▫ Principal reasons why dams are built: �Flood protection �Recreation �Industrial purposes �Electricity �Water supply �Political reason

Water is released from the Glen Canyon dam.

Impacts of dams on streams • traps the suspended and dissolved load, starving the area downstream of sediment and nutrients • a barrier to any aquatic life going up or down stream, which can prevent aquatic life from mating and reduce the diversity of wildlife upstream

• Flood Control: ▫ Channelization: Straightening out the meanders of a stream to for a straight line, or smoothing out the natural levee by replacing it with concrete flood walls. ▫ Artificial Levees: Artificially raising the height of a natural levee. Channelization Artificial leevee

• Urbanization ▫ When houses or businesses are built in a floodplain, they get flooded. ▫ Increases runoff into streams, which further increases the chances of flooding