Our Water Resources

Learning Objectives:

After the session, participants/learners will be able to: 1. Discuss briefly the hydrologic cycle.2. Recognized how water distributed on earth; 3. Identify the various water resources on earth;4. Explain how different activities affects the quality and availability of water.5. Suggest ways on conserving and protecting water resources.

Most of theEarthiscoveredby water

Evaporation and transpiration

Evaporation

Stream

InfiltrationWater tableInfiltration

Unconfined aquifer

Confined aquifer

Lake

Well requiring a pump

Flowingartesian well

Runoff

Precipitation

ConfinedRecharge Area

Aquifer

Less permeable materialsuch as clay Confirming permeable rock layer

Water Cycle – continuously collected, purified, recycled and distributed

How much How much water do water do we have?we have?

Supply of Water Resources

Small fraction (.014%) is readily available for human use

Glaciers

Glacier: large natural accumulation of land ice affected by present or past flowage

• Glacial ice has shaped many landforms in middle and high latitudes

• Glacial ice sheets affect global climate•Glaciers reflect sunlight•Glacial ice affects global heat transport

•Volume of glacial ice affects sea levels

• Large bodies of ice are plastic because of pressure on ice at bottom of mass

•Large body of ice can flow in response to gravity

• Ice on a slope can slide downwards

Why there is groundwater?

Strea

ms

Earth scientists use the term stream for all water flowing in a channel, regardless of the stream’s size. The term river is commonly used for any large stream fed by smaller ones, called tributaries. Most streams run year-round, even during times of drought, because they are fed by ground water that seeps into the streambed.

3 factors that control the stream velocity

Discharge

Gradient

Channel Characteristics

LakeA lake is a large, inland body of standing water that occupies the depression in the land surface.

Types of Lake

Oligotrophic

Eutrophic

WetlandsWetlands are areas where water covers the soil, or is present either at or near the surface of the soil all year or for varying periods of time during the year, including during the growing season.

Marine/Coastal Wetlands

Marine/Coastal Wetlands• Intertidal marshes; includes salt

marshes, saltings, raised salt marshes; includes tidal brackish and freshwater marshes.

• Intertidal forested wetlands; includes mangrove swamps, nipah swamps and tidal freshwater swamp forests.

• Coastal freshwater lagoons; includes freshwater delta lagoons.

Inland Wetlands• 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.

Human-made wetlands

• 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.

• Wastewater treatment areas; sewage farms, settling ponds, oxidation basins, etc.

• Canals and drainage channels, ditches.

Farming (41%)Public(10%)

Industry(11%)Power-

Plant (38%)Farming (85%)

Public (6%)

Industry(7%)

Power-Plant (2%)

U.S.A. China

As is evident from the comparison of water use in the U.S. and China, economic growth necessitates increasing use of water for power generation.

Source: Worldwatch Institute

The availability of water too is a limiting factor. An average human needs about 300,000 gallons of water annually, including 250,000 gallons for growing food. Indeed, nations with under 150,000 gallons of annual per capita water supply face severe limits to their growth.

Use of Water ResourcesHumans directly or indirectly use about 54% of

reliable runoffWithdraw 34% of reliable runoff for:• Agriculture – 70%• Industry – 20%• Domestic – 10%

Leave 20% of runoff in streams for human use:transport goods, dilute pollution, sustain fisheries

Could use up to 70-90% of the reliable runoff by 2025

Activities affects the quality and Activities affects the quality and availability of wateravailability of water

1.1.Deforestation and removal of Deforestation and removal of natural vegetationnatural vegetation

• Complete removal of natural vegetation Complete removal of natural vegetation from large stretches of land by converting from large stretches of land by converting forest into agricultural land, road forest into agricultural land, road construction, and upland developmentconstruction, and upland development

• Deforestation leads to loss of wildlife Deforestation leads to loss of wildlife habitats, micro-climate changes, loss of habitats, micro-climate changes, loss of production potential from a range of wood production potential from a range of wood and non-wood renewable resources, and and non-wood renewable resources, and potentially to erosion and loss of nutrientspotentially to erosion and loss of nutrients

2. Over-exploitation of vegetation for domestic use and commercial scale

• Contrary to “deforestation and removal of natural vegetation”, this does not involve the (near) complete removal of the “natural” vegetation, but rather a degradation of the remaining vegetation;

3. Inappropriate agricultural activities

• Improper management of cultivated arable land;

• It includes a wide variety of practices, such as absence or poor maintenance of control measures, improper crop rotation, shortening of the fallow period in kaingin cultivation, insufficient or excessive use of fertilizers and overuse of irrigation water;

• Degradation types commonly linked to this causative factor are soil erosion, soil compaction, soil nutrient loss, and water pollution (by sediments, pesticides, fertilizer)

4. Inappropriate forestry activities

• These activities reflect to the improper management of natural forests and tree plantations;

• This category would also include the replacement of a mixed natural forest with plantations of a very limited range of exotic species; and

5. Overgrazing

• The effect is usually soil compaction and/or a decrease of plant cover, both which may, in turn give rise to soil erosion and reduced infiltration of rainwater

6. Poor water resource management• The over extraction of water (for irrigation, urban

and industrial use) from rivers and other surface water resources has led to reduced downstream availability;

• Inefficient irrigation practices, wasteful urban/industrial water use and leakages from water delivery systems all contribute to water shortage problems, as does over-pumping of the aquifers;

• In coastal areas, over-extraction of groundwater has resulted in salt water intrusion into the freshwater aquifer (a growing problem in parts of Cebu)

7. Unregulated land conversion• Uncontrolled land development for

agricultural, residential, commercial and/or industrial purposes may contribute to degradation should such land uses or the management practices followed be unsuitable;

• Unregulated urban and industrial expansion within lowland agricultural areas may be contributory to watershed degradation

8. Industrial activities

• All human activities of a (bio)industrial nature: timber processing, factory farming (e.g. large-scale commercial poultry and piggery farms), power generation, mining, infrastructure and urbanization, waste handling, etc.

• It is most often linked to pollution of different kinds (either point source or non-profit); and

• In addition to possible chemical and organic pollutants, uncontrolled rainwater run-off from mine spoil heaps, unconsolidated roadside cuttings and embankments, urban and industrial sites can be the source of significant quantities of downstream sediments.

9. Inappropriate conservation technologies

• While the range of soil and water conservation, agroforestry and forestry technologies have been developed for upland areas, it implementation typically requires substantial investments in labor, time, money and material resources – items that many households do not have;

• Even when aware of the need to adopt specific sustainable land management practices, a household’s socio-economic constraints may prevent it from being in a position to do so; and

• There is a strong need to develop strategies and technologies that are cost effective, socio-culturally adaptive and ecologically friendly.

Assignment:

Search, list and at least 5 ways in conserving and protecting water resources