GROUND WATER || WATER MASSES || SIGNIFICANCE OF LAKES. PART FOUR

 

SUB TOPIC 2

SIGNIFICANCE OF LAKES.

1.     Means of communication:  large lakes like the Great Lakes of North America provide a cheap and convenient form of transport for heavy and bulky goods such as coal, iron, machinery, grains and timber.

2.     Source of water for irrigation:  fresh water lakes provide water for irrigation in areas where agriculture is practised.eg Lake Victoria is used to irrigate sugar plantation in Kakira in Uganda.

3.     Generation of hydroelectric power: some lakes, especially those made by people are used in production of hydroelectric power. E.g. At Jinja Uganda.

4.     Source of minerals: salt lakes provide valuable rock salt.eg at Mojave Desert and Dead Sea.

5.     Tourist attraction and health resorts:  some lakes provide best health resorts and tourist attraction. E.g. Lake Geneva, Lake Lugano, Lake Placid (New York), Lake Vatter.

6.     Source of food/source of fish:  many lakes are habitat to a variety of fish species.

7.     Moderation of climate: large and deep lake water regulates the climate of the area surrounding. These lakes influence temperatures and rainfall of the area.

8.     Source of rivers: some lakes are sources of rivers, which in turn become useful in the lands through which they flow. Example River Nile whose source is Lake Victoria. Blue Nile its source is Lake Tana.

9.     Provision of water for domestic and industrial use: most of water (fresh water) lakes provide water which is used in homes for drinking, cooking and cleaning.

10.  A lake also provides storage of water. Example dams constructed by man are used as storage facilities.

NEGATIVE EFFECTS.

1.     Some lakes provides habitat for disease vectors:  fresh water lakes provides habitat for the breeding of disease vectors.

2.     Transport barriers: some lakes can be an obstacle to land transport.

3.     Flooding: excessive rainfall can cause a lake to expand resulting in waters flooding the neighbouring shorelands.

SUB TOPIC 3

WETLANDS

According to RAMSAR convention “wetlands are areas of marsh, fen, peatland or water, whether natural or artificial, permanent or temporary with water that is static or flowing fresh, blackish or salt, including areas of marine water the depth of which at a low tides not exceed six meters”.

Wetlands are low –lying, depressional ecosystems that are permanently or periodically saturated with water at or close to the surface. They occurs typically in low lying areas that receive fresh water at the edges of lakes, ponds, streams and rivers or salt water from tides in coastal areas protected from waves.

Wetlands are varying greatly and are characterized depending on morphology, hydrology, water chemistry and type of vegetation dominated the areas. However these characters vary considerably regional wise to local wise.

NOTE: Wetlands are found in every continent except Antarctic and in climates ranging from the tropics 23°27´ N&S to the tundra. And in wetlands the surface of water table is at above or just below the land surface for enough time to promote the development of soil characteristics of wet environment.

 

CLASSIFICATION OF WETLANDS

Basing on location and origin in ramsar convention three main classifications of wetlands were put forward which includes marine/coastal wetlands, inland wetlands and human made wetlands.

MARINE/COASTAL WETLANDS

Permanent shallow marine waters in most cases less than six meters deep at low tide; include sea bays and straits, Marine sub tidal aquatic beds; includes kelp beds, sea-grass beds, and tropical marine meadows, Coral reefs, Rocky marine shores; includes rocky offshore islands, sea cliffs, Sand, shingle or pebble shores; includes sand bars, spits and sandy islets; includes dune systems and humid dune slacks, Estuarine waters; permanent water of estuaries and estuarine systems of deltas, Intertidal mud, sand or salt flats, Intertidal marshes; includes salt marshes, salt meadows, salting’s, raised salt marshes; includes tidal brackish and freshwater marshes, Intertidal forested wetlands; includes mangrove swamps, nipah swamps and tidal freshwater swamp forests, Coastal brackish/saline lagoons; brackish to saline lagoons with at least one relatively narrow connection to the sea, Coastal freshwater lagoons; includes freshwater delta lagoons and Karst and other subterranean hydrological systems, marine/coastal

INLAND WETLANDS

Permanent inland deltas, Permanent rivers/streams/creeks; includes waterfalls, Seasonal/intermittent/irregular rivers/streams/creeks, Permanent freshwater lakes (over 8 ha); includes large oxbow lakes, Seasonal/intermittent freshwater lakes (over 8 ha); includes floodplain lakes, Permanent saline/brackish/alkaline lakes, Seasonal/intermittent saline/brackish/alkaline lakes and flats, Permanent saline/brackish/alkaline ,Seasonal/intermittent saline/brackish/alkaline marshes/pools, Permanent freshwater marshes/pools; ponds (below 8 ha), marshes and swamps on inorganic soils; with emergent vegetation water-logged for at least most of the growing season, Seasonal/intermittent freshwater marshes/pools on inorganic soils; includes sloughs, potholes, seasonally flooded meadows, sedge marshes, Non-forested peat lands; includes shrub or open bogs, swamps, fens, Alpine wetlands; includes alpine meadows, temporary waters from snowmelt, Tundra wetlands; includes tundra pools, temporary waters from snowmelt, Shrub-dominated wetlands; shrub swamps, shrub-dominated freshwater marshes, shrub Carr, alder thicket on inorganic soils, Freshwater, tree-dominated wetlands; includes freshwater swamp forests, seasonally flooded forests, wooded swamps on inorganic soils, Forested peat lands; peat swamp forests, Freshwater springs; oases, Geothermal wetlands and Karst and other subterranean hydrological systems.

HUMAN-MADE WETLANDS

human made wetlands includes; Aquaculture (e.g., fish/shrimp) ponds, Ponds; includes farm ponds, stock ponds, small tanks; (generally below 8 ha), Irrigated land; includes irrigation channels and rice fields, Seasonally flooded agricultural land including intensively managed or grazed wet meadow or pasture, Salt exploitation sites; Salt pans, salines etc., Water storage areas; reservoirs/ barrages/ dams/ impoundments generally over 8 ha, Excavations; gravel/ brick/ clay pits; borrow pits, mining pools, Waste water treatment areas; sewage farms, settling, ponds, oxidation basin, etc., Canals and drainage channels, ditches, Karst and other subterranean hydrological systems.

From the major classification above there are three main types of wetlands which are swamps, marshes and fen & bogs. Each of these categories varies widely and since they depend on water source their boundaries can change.  However the main distinguishing characteristic includes vegetation, soil type, water supply and water chemistry.

ALSO READ THE FOLLOWING RELATED TOPIC

1. GROUND WATER || WATER MASSES || SOURCES OF GROUND WATER PART ONE
2. GROUND WATER || WATER MASSES || WELLS AND BOREHOLES: PART TWO
3. GROUND WATER || WATER MASSES || FORMATION AND CLASSIFICATION OF LAKES: PART THREE
4. GROUND WATER || WATER MASSES || SIGNIFICANCE OF LAKES. PART FOUR
5. GROUND WATER || WATER MASSES || IMPORTANCE OF WETLANDS PART FIVE
6. GROUND WATER || WATER MASSES || CORAL COASTS PART SIX