Types of Rural Resources Hydrological Resources:

Rainfall

Rain is liquid precipitation, as opposed to non-liquid kinds of precipitation such as snow, hail and sleet. Rain requires the presence of a thick layer of the atmosphere to have temperatures above the melting point of water near and above the Earth's surface. On Earth, it is the condensation of atmospheric water vapor into drops of water heavy enough to fall, often making it to the surface. Two processes, possibly acting together, can lead to air becoming saturated leading to rainfall: cooling the air or adding water vapor to the air. Virga is precipitation that begins falling to the earth but evaporates before reaching the surface; it is one of the ways air can become saturated. Precipitation forms via collision with other rain drops or ice crystals within a cloud. Rain drops range in size from oblate, pancake-like shapes for larger drops, to small spheres for smaller drops.

Moisture moving along three-dimensional zones of temperature and moisture contrasts known as weather fronts is the major method of rain production. If enough moisture and upward motion is present, precipitation falls from convective clouds (those with strong upward vertical motion) such as cumulonimbus (thunderstorms) which can organize into narrow rainbands. In mountainous areas, heavy precipitation is possible where upslope flow is maximized within windward sides of the terrain at elevation which forces moist air to condense and fall out as rainfall along the sides of mountains. On the leeward side of mountains, desert climates can exist due to the dry air caused by downslope flow which causes heating and drying of the air mass. The movement of the monsoon trough, or intertropical convergence zone, brings rainy seasons to savannah climes. Rain is the primary source of freshwater for most areas of the world, providing suitable conditions for diverse ecosystems, as well as water for hydroelectric power plants and crop irrigation. Rainfall is measured through the use of rain gauges. Rainfall amounts are estimated actively by weather radar and passively by weather satellites.

The urban heat island effect leads to increased rainfall, both in amounts and intensity, downwind of cities. Global warming is also causing changes in the precipitation pattern globally, including wetter conditions across eastern North America and drier conditions in the tropics. Precipitation is a major component of the water cycle, and is responsible for depositing most of the fresh water on the planet. The globally-averaged annual precipitation is 990 millimetres (39 in). Climate classification systems such as the Köppen climate classification system use average annual rainfall to help differentiate between differing climate regimes. Antarctica is the Earth's driest continent. Rain is also known or suspected on other worlds, composed of methane, iron, neon, and sulfuric acid rather than water.

Formation

Water-saturated air

How clouds form in response to a cold front

Air contains water vapor and the amount of water in a given mass of dry air, known as the Mixing Ratio, is measured in grams of water per kilogram of dry air (g/kg). The amount of moisture in air is also commonly reported as relative humidity; which is the percentage of the total water vapor air can hold at a particular air temperature. How much water vapor a parcel of air can contain before it becomes saturated (100% relative humidity) and forms into a cloud (a group of visible and tiny water and ice particles suspended above the Earth's surface) depends on its temperature. Warmer air can contain more water vapor than cooler air before becoming saturated. Therefore, one way to saturate a parcel of air is to cool it. The dew point is the temperature to which a parcel must be cooled in order to become saturated.

There are four main mechanisms for cooling the air to its dew point: adiabatic cooling, conductive cooling, radiational cooling, and evaporative cooling. Adiabatic cooling occurs when air rises and expands. The air can rise due to convection, large-scale atmospheric motions, or a physical barrier such as a mountain (orographic lift). Conductive cooling occurs when the air comes into contact with a colder surface, usually by being blown from one surface to another, for example from a liquid water surface to colder land. Radiational cooling occurs due to the emission of infrared radiation, either by the air or by the surface underneath. Evaporative cooling occurs when moisture is added to the air through evaporation, which forces the air temperature to cool to its wet-bulb temperature, or until it reaches saturation.

The main ways water vapor is added to the air are: wind convergence into areas of upward motion, precipitation or virga falling from above, daytime heating evaporating water from the surface of oceans, water bodies or wet land, transpiration from plants, cool or dry air moving over warmer water, and lifting air over mountains. Water vapor normally begins to condense on condensation nuclei such as dust, ice, and salt in order to form clouds. Elevated portions of weather fronts (which are three-dimensional in nature) force broad areas of upward motion within the Earth's atmosphere which form clouds decks such as altostratus or cirrostratus. Stratus is a stable cloud deck which tends to form when a cool, stable air mass is trapped underneath a warm air mass. It can also form due to the lifting of advection fog during breezy conditions.

Coalescence

The shape of rain drops depend upon their size

Coalescence occurs when water droplets fuse to create larger water droplets, or when water droplets freeze onto an ice crystal, which is known as the Bergeron

process. Air resistance typically causes the water droplets in a cloud to remain stationary. When air turbulence occurs, water droplets collide, producing larger droplets. As these larger water droplets descend, coalescence continues, so that

drops become heavy enough to overcome air resistance and fall as rain. Coalescence generally happens most often in clouds above freezing, and is also known as the warm rain process. In clouds below freezing, when ice crystals gain enough mass they begin to fall. This generally requires more mass than

coalescence when occurring between the crystal and neighboring water droplets. This process is temperature dependent, as supercooled water droplets only exist in a cloud that is below freezing. In addition, because of the great temperature difference between cloud and ground level, these ice crystals may melt as they fall and become rain.

Causes

Frontal activity: Stratiform (a broad shield of precipitation with a relatively similar intensity) and dynamic precipitation (convective precipitation which is showery in nature with large changes in intensity over short distances) occur as a consequence of slow ascent of air in synoptic systems (on the order of cm/s), such as in the vicinity of cold fronts and near and poleward of surface warm fronts. Similar ascent is seen around tropical cyclones outside of the eyewall, and in comma-head precipitation patterns around mid-latitude cyclones. A wide variety of weather can be found along an occluded front, with thunderstorms possible, but usually their passage is associated with a drying of the air mass. Occluded fronts usually form around mature low-pressure areas. What separates rainfall from other precipitation types, such as ice pellets and snow, is the presence of a thick layer of air aloft which is above the melting point of water, which melts the frozen precipitation well before it reaches the ground. If there is a shallow near surface layer that is below freezing, freezing rain (rain which freezes on contact with surfaces in subfreezing environments) will result. Hail becomes an increasingly infrequent occurrence when the freezing level within the atmosphere exceeds 11,000 feet (3,400 m) above ground level.

Convection

Convective precipitation

Convective rain, or showery precipitation, occurs from convective clouds, e.g., cumulonimbus or cumulus congestus. It falls as showers with rapidly changing intensity. Convective precipitation falls over a certain area for a relatively short time, as convective clouds have limited horizontal extent.

Most precipitation in the tropics appears to be convective; however, it has been suggested that stratiform precipitation also occurs. Graupel and hail indicate convection. In mid-latitudes, convective precipitation is intermittent and often associated with baroclinic boundaries such as cold fronts, squall lines, and warm fronts.

Orographic effects

Orographic precipitation

Orographic precipitation occurs on the windward side of mountains and is caused by the rising air motion of a large-scale flow of moist air across the

mountain ridge, resulting in adiabatic cooling and condensation. In mountainous parts of the world subjected to

relatively consistent winds (for example, the trade winds), a more moist climate usually prevails on the windward side of a mountain than on the leeward or downwind side. Moisture is removed by orographic lift, leaving drier air (see katabatic wind) on the descending and generally warming, leeward side where a rain shadow is observed. In Hawaii, Mount Waiʻaleʻale, on the island of Kauai, is notable for its extreme rainfall, as it has the second highest average annual rainfall on Earth, with 460 inches (12,000 mm). Systems known as Kona storms affect the state with heavy rains between October and April. Local climates vary considerably on

each island due to their topography, divisible into windward (Koʻolau) and leeward (Kona) regions based upon location relative to the higher mountains. Windward sides face the east to northeast trade winds and receive much more rainfall; leeward sides are drier and sunnier, with less rain and less cloud cover.

In South America, the Andes mountain range blocks Pacific moisture that arrives in that continent, resulting in a desertlike climate just downwind across western Argentina. The Sierra Nevada range creates the same effect in North America forming the Great Basin and Mojave Deserts.

Human influence

The fine particulate matter produced by car exhaust and other human sources of pollution forms cloud condensation nuclei, leads to the production of clouds and increases the likelihood of rain. As commuters and commercial traffic cause pollution to build up over the course of the week, the likelihood of rain increases: it peaks by Saturday, after five days of weekday pollution has been built up. In heavily populated areas that are near the coast, such as the United States' Eastern Seaboard, the effect can be dramatic: there is a 22% higher chance of rain on Saturdays than on Mondays. The urban heat island effect warms cities 0.6 °C (1.1 °F) to 5.6 °C (10.1 °F) above surrounding suburbs and rural areas. This extra heat leads to greater upward motion, which can induce additional shower and thunderstorm activity. Rainfall rates downwind of cities are increased between 48% and 116%. Partly as a result of this warming, monthly rainfall is about 28% greater between 20 miles (32 km) to 40 miles (64 km) downwind of cities, compared with upwind. Some cities induce a total precipitation increase of 51%.

Mean surface temperature anomalies during the period 1999 to 2008 with respect to the average temperatures from 1940 to 1980

Increasing temperatures tend to increase evaporation which can lead to more precipitation. Precipitation generally increased over land north of 30°N from 1900 through 2005 but has declined over the tropics since the 1970s. Globally there has been no statistically significant overall trend in precipitation over the past century, although trends have varied widely by region and over time. Eastern portions of North and South America, northern Europe, and northern and central Asia have become wetter. The Sahel, the Mediterranean, southern Africa and parts of southern Asia have become drier. There has been an increase in the number of heavy precipitation events over many areas during the past century, as well as an increase since the 1970s in the prevalence of droughts—especially in the tropics and subtropics. Changes in precipitation and evaporation over the oceans are suggested by the decreased salinity of mid- and high-latitude waters (implying more precipitation), along with increased salinity in lower latitudes (implying less precipitation and/or more evaporation). Over the contiguous United States, total annual precipitation increased at an average rate of 6.1 percent per century since 1900, with the greatest increases within the East North Central climate region

(11.6 percent per century) and the South (11.1 percent). Hawaii was the only region to show a decrease (-9.25 percent).

The most successful attempts at influencing weather involve cloud seeding which include techniques used to increase winter precipitation over mountains and suppress hail.[57]

Characteristics

Patterns

Rainbands are cloud and precipitation areas which are significantly elongated. Rainbands can be stratiform or convective, and are generated by differences in temperature. When noted on weather radar imagery, this precipitation elongation is referred to as banded structure. Rainbands in advance of warm occluded fronts and warm fronts are associated with weak upward motion, and tend to be wide and stratiform in nature.

Rainbands spawned near and ahead of cold fronts can be squall lines which are able to produce tornadoes. Rainbands associated with cold fronts can be warped by mountain barriers perpendicular to the front's orientation due to the formation of a low-level barrier jet. Bands of thunderstorms can form with sea breeze and land breeze boundaries, if enough moisture is present. If sea breeze rainbands become active enough just ahead of a cold front, they can mask the location of the cold front itself.

Once a cyclone occludes, a trough of warm air aloft, or "trowal" for short, will be caused by strong southerly winds on its eastern periphery rotating aloft around its northeast, and ultimately northwestern, periphery (also known as the warm conveyor belt), forcing a surface trough to continue into the cold sector on a similar curve to the occluded front. The trowal creates the portion of an occluded cyclone known as its comma head, due to the comma-like shape of the mid-tropospheric cloudiness that accompanies the feature. It can also be the focus of locally heavy precipitation, with thunderstorms possible if the atmosphere along the trowal is unstable enough for convection. Banding within the comma head precipitation pattern of an extratropical cyclone can yield significant amounts of rain. Behind extratropical cyclones during fall and winter, rainbands can form downwind of relative warm bodies of water such as the Great Lakes. Downwind of islands, bands of showers and thunderstorms can develop due to low level wind convergence downwind of the island edges. Offshore California, this has been noted in the wake of cold fronts.

Rainbands within tropical cyclones are curved in orientation. Tropical cyclone rainbands contain showers and thunderstorms that, together with the eyewall and the eye, constitute a hurricane or tropical storm. The extent of rainbands around a tropical cyclone can help determine the cyclone's intensity.

Acidity

The pH of rain varies, especially due to its origin. On Americas East Coast, rain that is derived from the Atlantic Ocean typically has a pH of 5.0-5.6; rain that comes across the continental from the west has a pH of 3.8-4.8; and local thunderstorms can have a pH as low as 2.0. Rain becomes acidic primarily due to the presence of two strong acids, sulfuric acid (H2SO4) and nitric acid (HNO3). Sulfuric acid is derived from natural sources such as volcanoes, and wetlands (sulfate reducing bacteria); and anthropogenic sources such as the

combustion of fossil fuels, and mining where H2S is present. Nitric acid is produced by natural sources such as lightning, soil bacteria, and natural fires; while also produced anthropogenically by the combustion of fossil fuels and from power plants. In the past 20 years the concentrations of nitric and sulfuric acid has decreased in presence of rainwater, which may be due to the significant increase in ammonium (most likely as ammonia from livestock production), which acts as a buffer in acid rain and raising the pH.

Köppen climate classification

The Köppen classification depends on average monthly values of temperature and precipitation. The most commonly used form of the Köppen classification has five primary types labeled A through E. Specifically, the primary types are A, tropical; B, dry; C, mild mid-latitude; D, cold mid-latitude; and E, polar. The five primary classifications can be further divided into secondary classifications such as rain forest, monsoon, tropical savanna, humid subtropical, humid continental, oceanic climate, Mediterranean climate, steppe, subarctic climate, tundra, polar ice cap, and desert.

Rain forests are characterized by high rainfall, with definitions setting minimum normal annual rainfall between 1,750 millimetres (69 in) and 2,000 millimetres (79 in). A tropical savanna is a grasslandbiome located in semi-arid to semi-humid climate regions of subtropical and tropical latitudes, with rainfall between 750 millimetres (30 in) and 1,270 millimetres (50 in) a year. They are widespread on Africa, and are also found in India, the northern parts of South America, Malaysia, and Australia. The humid subtropical climate zone where winter rainfall is associated with large storms that the westerlies steer from west to east. Most summer rainfall occurs during thunderstorms and from occasional tropical cyclones. Humid subtropical climates lie on the east side continents, roughly between latitudes 20° and 40° degrees away from the equator.

An oceanic (or maritime) climate is typically found along the west coasts at the middle latitudes of all the world's continents, bordering cool oceans, as well as southeastern Australia, and is accompanied by plentiful precipitation year round.[76] The Mediterranean climate regime resembles the climate of the lands in the Mediterranean Basin, parts of western North America, parts of Western and South Australia, in southwestern South Africa and in parts of central Chile. The climate is characterized by hot, dry summers and cool, wet winters.[77] A steppe is a dry grassland.[78] Subarctic climates are cold with continuous permafrost and little precipitation.[79]

Measurement

Gauges

The standard way of measuring rainfall or snowfall is the standard rain gauge, which can be found in 100-mm (4-in) plastic and 200-mm (8-in) metal varieties. The inner cylinder is filled by 25 mm (0.98 in) of rain, with overflow flowing into the outer cylinder. Plastic gages have markings on the inner cylinder down to 0.25 mm (0.0098 in) resolution, while metal gauges require use of a stick designed with the appropriate 0.25 mm (0.0098 in) markings. After the inner cylinder is filled, the amount inside it is discarded, then filled with the remaining rainfall in the outer cylinder until all the fluid in the outer cylinder is gone, adding to the overall total until the outer cylinder is empty. Other types of gauges include the popular wedge gauge (the cheapest rain gauge and

most fragile), the tipping bucket rain gauge, and the weighing rain gauge. For those looking to measure rainfall the most inexpensively, a can that is cylindrical with straight sides will act as a rain gauge if left out in the open, but its accuracy will depend on what ruler you use to measure the rain with. Any of the above rain gauges can be made at home, with enough know-how.

When a precipitation measurement is made, various networks exist across the United States and elsewhere where rainfall measurements can be submitted through the Internet, such as CoCoRAHS or GLOBE. If a network is not available in the area where one lives, the nearest local weather or met office will likely be interested in the measurement.

One millimeter of rainfall is the equivalent of one liter of water per square meter. This makes computing the water requirements of crops simple.

Remote sensing

Twenty-four hour rainfall accumulation on the Val d'Irène radar in Eastern Canada. Zones without data in the east and southwest are caused by beam blocking from mountains. (Source: Environment Canada)

Intensity

Rainfall intensity is classified according to the rate of precipitation:

Light rain — when the precipitation rate is < 2.5 millimetres (0.098 in) per hour Moderate rain — when the precipitation rate is between 2.5 millimetres (0.098 in) - 7.6 millimetres (0.30 in) or

10 millimetres (0.39 in) per hour Heavy rain — when the precipitation rate is > 7.6 millimetres (0.30 in) per hour, or between 10 millimetres

(0.39 in) and 50 millimetres (2.0 in) per hour Violent rain — when the precipitation rate is > 50 millimetres (2.0 in) per hour

Forecasting

Example of a five day rainfall forecast from the Hydrometeorological Prediction Center

The Quantitative Precipitation Forecast (abbreviated QPF) is the expected amount of liquid precipitation accumulated over a specified time period over a specified area. A QPF will be specified when a measurable precipitation type reaching a minimum threshold is forecast for any hour during a QPF valid period. Precipitation forecasts tend to be bound by synoptic hours such as 0000, 0600, 1200 and 1800 GMT. Terrain is considered in QPFs by use of topography or based upon climatological precipitation patterns from observations with fine detail. Starting in the mid to late 1990s, QPFs were used within hydrologic forecast models to simulate impact to rivers throughout the United States. Forecast models show significant sensitivity to humidity levels within the planetary boundary layer, or in the lowest levels of the atmosphere, which decreases with height. QPF can be generated on a quantitative, forecasting amounts, or a qualitative, forecasting the probability of a specific amount, basis. Radar imagery forecasting techniques show higher skill than model forecasts within 6 to 7 hours of the time of the radar image. The forecasts can be verified through use of rain gauge measurements,

weather radar estimates, or a combination of both. Various skill scores can be determined to measure the value of the rainfall forecast.

Impact

Effect on agriculture

Rainfall estimates for southern Japan and the surrounding region from July 20–27, 2009.

Precipitation, especially rain, has a dramatic effect on agriculture. All plants need at least some water to survive, therefore rain (being the most effective means of watering) is important to agriculture. While a regular rain pattern is usually vital to healthy plants, too much or too little rainfall can be harmful, even devastating to crops. Drought can kill crops and increase erosion, while overly wet weather can cause harmful fungus growth. Plants need varying amounts of rainfall to survive. For example, certain cacti require small amounts of water, while tropical plants may need up to hundreds of inches of rain per year to survive.

In areas with wet and dry seasons, soil nutrients diminish and erosion increases during the wet season. Animals have adaptation and survival strategies for the wetter regime. The previous dry season leads to food shortages into the wet season, as the crops have yet to mature. Developing countries have noted that their populations show seasonal weight fluctuations due to food shortages seen before the first harvest, which occurs late in the wet season. Rain may be harvested through the use of rainwater tanks; treated to potable use or for non-potable use indoors or for irrigation,. Excessive rain during short periods of time can cause flash floods.[108]

Global climatology

Approximately 505,000 cubic kilometres (121,000 cu mi) of water falls as precipitation each year across the globe with 398,000 cubic kilometres (95,000 cu mi) of it over the oceans. Given the Earth's surface area, that means the globally-averaged annual precipitation is 990 millimetres (39 in). Deserts are defined as areas with an average annual precipitation of less than 250 millimetres (10 in) per year, or as areas where more water is lost by evapotranspiration than falls as precipitation.

Deserts

The northern half of Africa is primarily desert or arid, containing the Sahara. Across Asia, a large annual rainfall minimum, composed primarily of deserts, stretches from the Gobi desert in Mongolia west-southwest through Pakistan and Iran into the Arabian desert in Saudi Arabia. Most of Australia is semi-arid or desert,[119] making it the world's driest continent. In South America, the Andes mountain range blocks Pacific moisture that arrives in that continent, resulting in a desertlike climate just downwind across western Argentina.[40] The drier areas of the United States are regions where the Sonoran desert overspreads the Desert Southwest, the Great Basin and central Wyoming.[120]

Wetlands

The equatorial region near the Intertropical Convergence Zone (ITCZ), or monsoon trough, is the wettest portion of the world's continents. Annually, the rain belt within the tropics marches northward by August, then moves back southward into the Southern Hemisphere by February and March. Within Asia, rainfall is favored across its southern portion from India east and northeast across the Philippines and southern China into Japan due to the monsoon advecting moisture primarily from the Indian Ocean into the region. The monsoon trough can reach as far north as the 40th parallel in East Asia during August before moving southward thereafter. Its poleward progression is accelerated by the onset of the summer monsoon which is characterized by the development of lower air pressure (a thermal low) over the warmest part of Asia. Similar, but weaker, monsoon circulations are present over North America and Australia. During the summer, the Southwest monsoon combined with Gulf of California and Gulf of Mexico moisture moving around the subtropical ridge in the Atlantic ocean bring the promise of afternoon and evening thunderstorms to the southern tier of the United States as well as the Great Plains.[127] The eastern half of the contiguous United States east of the 98th meridian, the mountains of the Pacific Northwest, and the Sierra Nevada range are the wetter portions of the nation, with average rainfall exceeding 30 inches (760 mm) per year. Tropical cyclones enhance precipitation across southern sections of the United States, as well as Puerto Rico, the United States Virgin Islands, the Northern Mariana Islands, Guam, and American Samoa.

Runoff

If the amount of water falling on the ground is greater than the infiltration rate of the surface, runoff or overland flow will occur. Runoff specifically refers to the water leaving an area of drainage and flowing across the land surface to points of lower elevation. It is not the water flowing beneath the surface of the ground. This type of water flow is called throughflow. Runoff involves the following events:

Rainfall intensity exceeds the soil's infiltration rate and water begins accumulating at ground surface. Accumulating water causes a thin layer of water to form. This water layer begins to move downslope because of

gravity. Flowing water accumulates into larger depressions on the ground surface. Depressions fill up and overflow forming small rills. Rills join to form larger streams and rivers. Streams and rivers flow until they eventually empty into lakes or oceans.

On a global scale, runoff occurs because of the imbalance between evaporation and precipitation over the Earth's land and ocean surfaces. Oceans make up 71% of the Earth's surface and the solar radiation received here powers the global evaporation process. In fact, 86% of the Earth's evaporation occurs over the oceans, while only 14% occurs over land. Of the total amount of water evaporated into the atmosphere, precipitation returns only 79% to the oceans, and 21% to the land. Surface runoff sends 7% of the land-based precipitation back to the ocean to balance the processes of evaporation and precipitation.

The distribution of runoff per continent shows some interesting patterns (see Table 1). Areas having the most runoff are those with high rates of precipitation and low rates of evaporation.

Streamflow and Stream Discharge

Figure 1: Stream hydrograph. (Source: PhysicalGeography.net)

The term streamflow describes the process of water flowing in the organized channels of a stream or river. Stream discharge represents the volume of water passing through a river channel during a certain

period of time. Stream discharge can be expressed mathematically with the following equation:

Q = W x D x V

where, Q equals stream discharge usually measured in cubic meters per second, W equals channel width, D equals channel depth, and V equals velocity of flowing water.

Because of streamflow's potential hazard to humans, many streams are gauged by mechanical recorders. These instruments record the stream's discharge on a hydrograph. The graph in Figure 1 illustrates a typical hydrograph and its measurement of discharge over time.

From this graph we can observe the following:

A small blip caused by rain falling directly into the channel is the first evidence that stream discharge is changing because of the rainfall.

A significant time interval occurs between the start of rain and the beginning of the main rise in discharge on the hydrograph. This lag occurs because of the time required for the precipitation that falls in the stream's basin to eventually reach the recording station. Usually, the larger the basin the greater the the time lag.

The rapid movement of surface runoff into the stream's channels and subsequent flow causes the discharge to rise quickly.

The falling limb of the hydrograph tends to be less steep than the rise. This flow represents the water added from distant tributaries and from throughflow that occurs in surface soils and sediments.

After some time the hydrograph settles at a constant level known as base flow stage. Most of the base flow comes from groundwater flow which moves water into the stream channel very slowly.

Not all hydrographs are the same. Actually, the shape and magnitude of the hydrograph is controlled by two sets of factors:

Permanent Factors – slope of basin, soil structure, vegetation, channel density, etc. Transient Factors – those factors associated with precipitation input – size of storm, intensity, duration of

rainfall, etc.

Water Requirements and Storage

Water Storage

Summary: A do-it-yourself guide to designing, building, and maintaining your water tank, cistern or pond, and sustainably managing groundwater storage. It will help you with your independent water system, fire protection, and disaster preparedness, at low cost and using principles of ecological design. Includes building instructions for several styles of ferrocement water tanks.

Reviews

Storage that's low cost, low maintenance, high reliability, and high quality...the keys are right here in your hands. If you run a water system, for a weekend shack or a whole community, you need this book! —Doug Pratt, Real Goods Technical Editor

Introduction

Water Storage describes how to store water for home, farm, and small communities. It will help you design storage for just about any use, including fire safety and emergency, in just about any context—urban, rural, or village.

This includes:

general principles to help you design, construct, and use any water system a look at common mistakes and how to avoid them how the different kinds of storage can serve you—tanks, groundwater, and ponds how to determine the optimum amount of storage for your needs how to determine the best shape and material for your storage how to manage aquifers sustainably for inexpensive storage of water in the ground plumbing details for inlets, outlets, drains, overflows, access, etc. storage accessories and gadgets such as automatic shut-off valves, remote level indicators, ozonators, and filters how to build your own high-quality tank from ferrocement original design innovations—published here for the first time—to improve the quality of stored water, increase

water security, make maintenance easier, and reduce environmental impacts real-life examples of storage designs for a wide range of contexts

Thinking About Water

To achieve your design goals for a water system, it is helpful to know what your goals are. The first order of business is to consider:

Why Store Water?

Nearly all water systems include some form of storage, most commonly a tank. Storage can be used to:

cover peaks in demand smooth out variations in supply provide water security in case of supply interruptions or disaster save your home from fire meet legal requirements improve water quality provide thermal storage and freeze protection enable a smaller pipe to serve for a distant source

We're going to consider each of these reasons to store water, then look at design principles to help you frame the goals for your project.

Cover Peaks in Demand

The most common function of water storage is to cover short-term use flows that are greater than the flow of the water source. For example, a tiny, one gallon-per-minute spring supplies 1440 gallons a day. This is several times more than most homes use in a day. However, almost every fixture in the home consumes water at a faster rate than 1 gpm while it is turned on. Even a low-flow shower head uses about 1.5 gpm.

By using water stored in a tank, you can supply water to the shower faster than it is flowing from the spring. On completing the shower, the water will be coming in faster than it is going out, and the tank level will rise back up.

If you had a 10,000 gal tank, you could run a 100 gpm fire hose—creating the kind of blast used to bowl over hostile crowds—on the stored water from this tiny spring, for an hour and a half! Hopefully the fire would be out by then, as the tank would take several days to refill.

Smooth Out Variations in Supply

In some circumstances, your storage needs will be affected by variations in the water supply. For instance, if the supply is rainwater, you will need enough storage to make it through the intervals between rainfalls. A six-month, rainless dry season requires a heck of a lot more storage than the most common kind of variable supply—a well pump that cycles on and off.

If you have a well that taps stored groundwater, a tank will save wear and tear on your pump, because the pump won't have to switch on and off every time you open a tap.

Provide Water Security in Case of Supply Interruptions or Disaster

In many places, the water supply chain from source to tap is long and made of many delicate links. If a cow steps on the supply line, a pump breaks, a wire works loose, the electricity goes out, the city misplaces your check, or there is a natural disaster, your water flow could stop. By locating your storage as few chain links away as possible from your use point, a large measure of security is added...

Thinking About Water

Why Store Water? Cover Peaks in Demand • Smooth Out Variations in Supply • Provide Water Security in Case of Supply Interruptions or Disaster • Save Your Home from Fire • Meet Legal Requirements • Improve Water Quality • Provide Thermal Storage and Freeze Protection • Enable a Smaller Pipe to Serve for a Distant Source Design Principles Water System Design • Performance and Security Standard • Running Water People, Still Water People • Separate Handling for Different Qualities of Water • Design Horizon • Design for Failure, Design for Change • Where the Stuff in Water Ends Up • What Do You Have? What Can You Find? How Water Quality Changes in Storage Ways to Improve Water Quality in Storage • Hazardous Disinfection Byproducts• Effects of Heating • Bacterial Regrowth • The Problem of Leaching • Water Age • How to Test Stored Water

Ways to Store Water

Source Direct (No Storage) Store Water in Soil Store Water in Aquifers How Water Gets into and Moves through Aquifers • How to Increase the Amount of Water in Your Aquifer • Conjunctive Use • Sustainable management of groundwater • Overdrafting, Mining Fossil Groundwater • Protecting Groundwater Quality Store Water in Ponds Types of Man-Made Ponds and Where to Put Them • Pond Water Sources • Evaporation • Pond Size • Pond Depth • Pond Shape • Pond Inlets and Outlets • Pond Liners • Levee Construction • Wildlife and Ponds • Sport Fish in Ponds • Pond Maintenance

Water resources Water resources are sources of water that are useful or potentially useful to humans. Uses of water include agricultural, industrial, household, recreational and environmental activities. Virtually all of these human uses require fresh water.

97% of water on the Earth is salt water, and only 3% as fresh water of which slightly over two thirds is frozen in glaciers and polar ice caps. The remaining unfrozen fresh water is mainly found as groundwater, with only a small fraction present above ground or in the air.[2]

Fresh water is a renewable resource, yet the world's supply of clean, fresh water is steadily decreasing. Water demand already exceeds supply in many parts of the world and as the world population continues to rise, so too does the water demand. Awareness of the global importance of preserving water for ecosystem services has only recently emerged as, during the 20th century, more than half the world’s wetlands have been lost along with their valuable environmental services. Biodiversity-rich freshwater ecosystems are currently declining faster than marine or land ecosystems.[3] The framework for allocating water resources to water users (where such a framework exists) is known as water rights.

Sources of fresh water

Surface water

Surface water is water in a river, lake or fresh water wetland. Surface water is naturally replenished by precipitation and naturally lost through discharge to the oceans, evaporation, and sub-surface seepage.

Although the only natural input to any surface water system is precipitation within its watershed, the total quantity of water in that system at any given time is also dependent on many other factors. These factors include storage capacity in lakes, wetlands and artificial reservoirs, the permeability of the soil beneath these storage bodies, the runoff characteristics of the land in the watershed, the timing of the precipitation and local evaporation rates. All of these factors also affect the proportions of water lost.

Human activities can have a large and sometimes devastating impact on these factors. Humans often increase storage capacity by constructing reservoirs and decrease it by draining wetlands. Humans often increase runoff quantities and velocities by paving areas and channelizing stream flow.

The total quantity of water available at any given time is an important consideration. Some human water users have an intermittent need for water. For example, many farms require large quantities of water in the spring, and no water at all in the winter. To supply such a farm with water, a surface water system may require a large storage capacity to collect water throughout the year and release it in a short period of time. Other users have a continuous need for water, such as a power plant that requires water for cooling. To supply such a power plant with water, a surface water system only needs enough storage capacity to fill in when average stream flow is below the power plant's need.

Nevertheless, over the long term the average rate of precipitation within a watershed is the upper bound for average consumption of natural surface water from that watershed.

Natural surface water can be augmented by importing surface water from another watershed through a canal or pipeline. It can also be artificially augmented from any of the other sources listed here, however in practice the quantities are negligible. Humans can also cause surface water to be "lost" (i.e. become unusable) through pollution.

Brazil is the country estimated to have the largest supply of fresh water in the world, followed by Russia and Canada.

Under river flow

Throughout the course of the river, the total volume of water transported downstream will often be a combination of the visible free water flow together with a substantial contribution flowing through sub-surface rocks and gravels that underlie the river and its floodplain called the hyporheic zone. For many rivers in large valleys, this unseen component of flow may greatly exceed the visible flow. The hyporheic zone often forms a dynamic interface between surface water and true ground-water receiving water from the ground water when aquifers are fully charged and contributing water to ground-water when ground waters are depleted. This is especially significant in karst areas where pot-holes and underground rivers are common.

Ground water

Sub-surface water, or groundwater, is fresh water located in the pore space of soil and rocks. It is also water that is flowing within aquifers below the water table. Sometimes it is useful to make a distinction between sub-surface water that is closely associated with surface water and deep sub-surface water in an aquifer (sometimes called "fossil water").

Sub-surface water can be thought of in the same terms as surface water: inputs, outputs and storage. The critical difference is that due to its slow rate of turnover, sub-surface water storage is generally much larger compared to inputs than it is for surface water. This difference makes it easy for humans to use sub-surface water unsustainably for a long time without severe consequences. Nevertheless, over the long term the average rate of

seepage above a sub-surface water source is the upper bound for average consumption of water from that source.

The natural input to sub-surface water is seepage from surface water. The natural outputs from sub-surface water are springs and seepage to the oceans.

If the surface water source is also subject to substantial evaporation, a sub-surface water source may become saline. This situation can occur naturally under endorheic bodies of water, or artificially under irrigated farmland. In coastal areas, human use of a sub-surface water source may cause the direction of seepage to ocean to reverse which can also cause soil salinization. Humans can also cause sub-surface water to be "lost" (i.e. become unusable) through pollution. Humans can increase the input to a sub-surface water source by building reservoirs or detention ponds.

Desalination

Desalination is an artificial process by which saline water (generally sea water) is converted to fresh water. The most common desalination processes are distillation and reverse osmosis. Desalination is currently expensive compared to most alternative sources of water, and only a very small fraction of total human use is satisfied by desalination. It is only economically practical for high-valued uses (such as household and industrial uses) in arid areas. The most

Several schemes have been proposed to make use of icebergs as a water source, however to date this has only been done for novelty purposes. Glacier runoff is considered to be surface water.

The Himalayas, which are often called "The Roof of the World", contain some of the most extensive and rough high altitude areas on Earth as well as the greatest area of glaciers and permafrost outside of the poles. Ten of Asia’s largest rivers flow from there, and more than a billion people’s livelihoods depend on them. To complicate matters, temperatures are rising more rapidly here than the global average. In Nepal the temperature has risen with 0.6 degree over the last decade, whereas the global warming has been around 0.7 over the last hundred years.

Uses of fresh water

Uses of fresh water can be categorized as consumptive and non-consumptive (sometimes called "renewable"). A use of water is consumptive if that water is not immediately available for another use. Losses to sub-surface seepage and evaporation are considered consumptive, as is water incorporated into a product (such as farm produce). Water that can be treated and returned as surface water, such as sewage, is generally considered non-consumptive if that water can be put to additional use.

Agricultural

It is estimated that 69% of worldwide water use is for irrigation, with 15-35% of irrigation withdrawals being unsustainable. In some areas of the world irrigation is necessary to grow any crop at all, in other areas it permits more profitable crops to be grown or enhances crop yield. Various irrigation methods involve different trade-offs between crop yield, water consumption and capital cost of equipment and structures. Irrigation methods

such as furrow and overhead sprinkler irrigation are usually less expensive but are also typically less efficient, because much of the water evaporates, runs off or drains below the root zone. Other irrigation methods considered to be more efficient include drip or trickle irrigation, surge irrigation, and some types of sprinkler systems where the sprinklers are operated near ground level. These types of systems, while more expensive, usually offer greater potential to minimize runoff, drainage and evaporation. Any system that is improperly managed can be wasteful, all methods have the potential for high efficiencies under suitable conditions, appropriate irrigation timing and management. One issue that is often insufficiently considered is salinization of sub-surface water.

Aquaculture is a small but growing agricultural use of water. Freshwater commercial fisheries may also be considered as agricultural uses of water, but have generally been assigned a lower priority than irrigation (see Aral Sea and Pyramid Lake).

As global populations grow, and as demand for food increases in a world with a fixed water supply, there are efforts underway to learn how to produce more food with less water, through improvements in irrigation methodsand technologies, agricultural water management, crop types, and water monitoring.

Industrial

It is estimated that 22% of worldwide water use is industrial. Major industrial users include power plants, which use water for cooling or as a power source (i.e. hydroelectric plants), ore and oil refineries, which use water in chemical processes, and manufacturing plants, which use water as a solvent. The portion of industrial water usage that is consumptive varies widely, but as a whole is lower than agricultural use.

Water is used in power generation. Hydroelectricity is electricity obtained from hydropower. Hydroelectric power comes from water driving a water turbine connected to a generator. Hydroelectricity is a low-cost, non-polluting, renewable energy source. The energy is supplied by the sun. Heat from the sun evaporates water, which condenses as rain in higher altitudes, from where it flows down.

Pressurized water is used in water blasting and water jet cutters. Also, very high pressure water guns are used for precise cutting. It works very well, is relatively safe, and is not harmful to the environment. It is also used in the cooling of machinery to prevent over-heating, or prevent saw blades from over-heating.

Water is also used in many industrial processes and machines, such as the steam turbine and heat exchanger, in addition to its use as a chemical solvent. Discharge of untreated water from industrial uses is pollution. Pollution includes discharged solutes (chemical pollution) and discharged coolant water (thermal pollution). Industry requires pure water for many applications and utilizes a variety of purification techniques both in water supply and discharge.

Household

Drinking water

It is estimated that 8% of worldwide water use is for household purposes[6]. These include drinking water, bathing, cooking, sanitation, and gardening. Basic household water requirements have been estimated by Peter Gleick at around 50 liters per person per day, excluding water for gardens. Drinking water is water that is of sufficiently high quality so that it can be consumed or used without risk of immediate or long term harm. Such water is commonly called potable water. In most developed countries, the water supplied to households, commerce and industry is all of drinking water standard even though only a very small proportion is actually consumed or used in food preparation.

Recreation

Whitewater rapids

Recreational water use is usually a very small but growing percentage of total water use. Recreational water use is mostly tied to reservoirs. If a reservoir is kept fuller than it would otherwise be for recreation, then the water retained could be categorized as recreational usage. Release of water from a few reservoirs is also timed to enhance whitewater boating, which also could be considered a recreational usage. Other examples are anglers, water skiers, nature enthusiasts and swimmers.

Recreational usage is usually non-consumptive. Golf courses are often targeted as using excessive amounts of water, especially in drier regions. It is, however, unclear whether recreational irrigation (which would include private gardens) has a noticeable effect on water resources. This is largely due to the unavailability of reliable data. Additionally, many golf courses utilize either primarily or exclusively treated effluent water, which has little impact on potable water availability.

Some governments, including the Californian Government, have labelled golf course usage as agricultural in order to deflect environmentalists' charges of wasting water. However, using the above figures as a basis, the actual statistical effect of this reassignment is close to zero. In Arizona, an organized lobby has been established in the form of the Golf Industry Association, a group focused on educating the public on how golf impacts the environment.

Recreational usage may reduce the availability of water for other users at specific times and places. For example, water retained in a reservoir to allow boating in the late summer is not available to farmers during the spring planting season. Water released for whitewater rafting may not be available for hydroelectric generation during the time of peak electrical demand. Environmental: Explicit environmental water use is also a very small but growing percentage of total water use. Environmental water usage includes artificial wetlands, artificial lakes intended to create wildlife habitat, fish ladders , and water releases from reservoirs timed to help fish spawn.

Like recreational usage, environmental usage is non-consumptive but may reduce the availability of water for other users at specific times and places. For example, water release from a reservoir to help fish spawn may not be available to farms upstream.

Water stress

The concept of water stress is relatively simple: According to the World Business Council for Sustainable Development, it applies to situations where there is not enough water for all uses, whether agricultural, industrial or domestic. Defining thresholds for stress in terms of available water per capita is more complex, however, entailing assumptions about water use and its efficiency. Nevertheless, it has been proposed that when

annual per capita renewable freshwater availability is less than 1,700 cubic meters, countries begin to

Best estimate of the share of people in developing countries with access to drinking water 1970–2000.

experience periodic or regular water stress. Below 1,000 cubic meters, water scarcity begins to hamper economic development and human health and well-being.

Population growth

In 2000, the world population was 6.2 billion. The UN estimates that by 2050 there will be an additional 3.5 billion people with most of the growth in developing countries that already suffer water stress.[9] Thus, water demand will increase unless there are corresponding increases in water conservation and recycling of this vital resource.[10]

Expansion of business activity

Business activity ranging from industrialization to services such as tourism and entertainment continues to expand rapidly. This expansion requires increased water services including both supply and sanitation, which can lead to more pressure on water resources and natural ecosystems.

Rapid urbanization

The trend towards urbanization is accelerating. Small private wells and septic tanks that work well in low-density communities are not feasible within high-density urban areas. Urbanization requires significant investment in water infrastructure in order to deliver water to individuals and to process the concentrations of wastewater – both from individuals and from business. These polluted and contaminated waters must be treated or they pose unacceptable public health risks.

In 60% of European cities with more than 100,000 people, groundwater is being used at a faster rate than it can be replenished.[11] Even if some water remains available, it costs more and more to capture it.

Climate change

Climate change could have significant impacts on water resources around the world because of the close connections between the climate and hydrological cycle. Rising temperatures will increase evaporation and lead to increases in precipitation, though there will be regional variations in rainfall. Overall, the global supply of

freshwater will increase. Both droughts and floods may become more frequent in different regions at different times, and dramatic changes in snowfall and snow melt are expected in mountainous areas. Higher temperatures will also affect water quality in ways that are not well understood. Possible impacts include increased eutrophication. Climate change could also mean an increase in demand for farm irrigation, garden sprinklers, and perhaps even swimming pools

Depletion of aquifers

Due to the expanding human population, competition for water is growing such that many of the worlds major aquifers are becoming depleted. This is due both for direct human consumption as well as agricultural irrigation by groundwater. Millions of pumps of all sizes are currently extracting groundwater throughout the world. Irrigation in dry areas such as northern China and India is supplied by groundwater, and is being extracted at an unsustainable rate. Cities that have experienced aquifer drops between 10 to 50 meters include Mexico City, Bangkok, Manila, Beijing, Madras and Shanghai.[12]

Pollution and water protection

Polluted water

Water pollution is one of the main concerns of the world today. The governments of many countries have striven to find solutions to reduce this problem. Many pollutants threaten water supplies, but the most widespread, especially in underdeveloped countries, is the discharge of raw sewage into natural waters; this method of sewage disposal is the most common method in underdeveloped countries, but also is prevalent in quasi-developed countries such as China, India and Iran. Sewage, sludge, garbage, and even toxic pollutants are all dumped into the water. Even if sewage is treated, problems still arise. Treated sewage forms sludge, which may be placed in landfills, spread out on land, incinerated or dumped at sea. In addition to sewage, nonpoint source pollution such as agricultural runoff is a significant source of pollution in some parts of the world, along with urban stormwater runoff and chemical wastes dumped by industries and governments.

Water and conflict

The only known example of an actual inter-state conflict over water took place between 2500 and 2350 BC between the Sumerian states of Lagash and Umma.[14] Yet, despite the lack of evidence of international wars being fought over water alone, water has been the source of various conflicts throughout history. When water scarcity causes political tensions to arise, this is referred to as water stress. Water stress has led most often to conflicts at local and regional levels. Using a purely quantitative methodology, Thomas Homer-Dixon successfully correlated water scarcity and scarcity of available arable lands to an increased chance of violent conflict.

Water stress can also exacerbate conflicts and political tensions which are not directly caused by water. Gradual reductions over time in the quality and/or quantity of fresh water can add to the instability of a region by depleting the health of a population, obstructing economic development, and exacerbating larger conflicts.

Conflicts and tensions over water are most likely to arise within national borders, in the downstream areas of distressed river basins. Areas such as the lower regions of China's Yellow River or the Chao Phraya River in Thailand, for example, have already been experiencing water stress for several years. Additionally, certain arid countries which rely heavily on water for irrigation, such as China, India, Iran, and Pakistan, are particularly at risk of water-related conflicts. Political tensions, civil protest, and violence may also occur in reaction to water privatization. The Bolivian Water Wars of 2000 are a case in point.

World water supply and distribution

Food and water are two basic human needs. However, global coverage figures from 2002 indicate that, of every 10 people:

roughly 5 have a connection to a piped water supply at home (in their dwelling, plot or yard); 3 make use of some other sort of improved water supply, such as a protected well or public standpipe; 2 are unserved; In addition, 4 out of every 10 people live without improved sanitation.

At Earth Summit 2002 governments approved a Plan of Action to:

Halve by 2015 the proportion of people unable to reach or afford safe drinking water. The Global Water Supply and Sanitation Assessment 2000 Report (GWSSAR) defines "Reasonable access" to water as at least 20 liters per person per day from a source within one kilometer of the user’s home.

Halve the proportion of people without access to basic sanitation. The GWSSR defines "Basic sanitation" as private or shared but not public disposal systems that separate waste from human contact.

As the picture shows, in 2025, water shortages will be more prevalent among poorer countries where resources are limited and population growth is rapid, such as the Middle East, Africa, and parts of Asia. By 2025, large urban and peri-urban areas will require new infrastructure to provide safe water and adequate sanitation. This suggests growing conflicts with agricultural water users, who currently consume the majority of the water used by humans.

Generally speaking the more developed countries of North America, Europe and Russia will not see a serious threat to water supply by the year 2025, not only because of their relative wealth, but more importantly their populations will be better aligned with available water resources. North Africa, the Middle East, South Africa and northern China will face very severe water shortages due to physical scarcity and a condition of overpopulation relative to their carrying capacity with respect to water supply. Most of South America, Sub-Saharan Africa, Southern China and India will face water supply shortages by 2025; for these latter regions the causes of scarcity will be economic constraints to developing safe drinking water, as well as excessive population growth.

1.6 billion people have gained access to a safe water source since 1990. The proportion of people in developing countries with access to safe water is calculated to have improved from 30 percent in 1970 to 71 percent in 1990, 79 percent in 2000 and 84 percent in 2004. This trend is projected to continue.

Economic considerations

Water supply and sanitation require a huge amount of capital investment in infrastructure such as pipe networks, pumping stations and water treatment works. It is estimated that Organisation for Economic Co-operation and Development (OECD) nations need to invest at least USD 200 billion per year to replace aging water infrastructure to guarantee supply, reduce leakage rates and protect water quality.

International attention has focused upon the needs of the developing countries. To meet the Millennium Development Goals targets of halving the proportion of the population lacking access to safe drinking water and basic sanitation by 2015, current annual investment on the order of USD 10 to USD 15 billion would need to be roughly doubled. This does not include investments required for the maintenance of existing infrastructure. Once infrastructure is in place, operating water supply and sanitation systems entails significant ongoing costs to cover personnel, energy, chemicals, maintenance and other expenses. The sources of money to meet these capital and operational costs are essentially either user fees, public funds or some combination of the two.

But this is where the economics of water management start to become extremely complex as they intersect with social and broader economic policy. Such policy questions are beyond the scope of this article, which has concentrated on basic information about water availability and water use. They are, nevertheless, highly relevant to understanding how critical water issues will affect business and industry in terms of both risks and opportunities.

Business response

The World Business Council for Sustainable Development in its H2OScenarios engaged in a scenario building process to:

Clarify and enhance understanding by business of the key issues and drivers of change related to water. Promote mutual understanding between the business community and non-business stakeholders on water

management issues. Support effective business action as part of the solution to sustainable water management.

It concludes that:

Business cannot survive in a society that thirsts. One does not have to be in the water business to have a water crisis. Business is part of the solution, and its potential is driven by its engagement. Growing water issues and complexity will drive up costs.

Land Resources The most important natural resource, upon which all human activity is based since time immemorial, is land. Man.s

inexorable progress towards development has, however, considerably damaged our land resource base. Further, land also suffers from various kinds of soil erosion, degradation and deforestation. The estimates of extent of area suffering from land degradation vary from 38.40 m.ha. to 187 m.ha. NRSA has estimated the extent of wastelands to be 63.85 m.ha which is about 20% of the total geographical area. To harness

the full potential of the available land resources and prevent its further degradation, wasteland development is of great significance. The problem of degraded land and its management is complex and multi-dimensional and its development requires a scientific, holistic and innovative approach. Unprecedented population pressures and demands of society on scarce land, water and biological resources and the increasing degradation of these resources is affecting the stability and resilience of our ecosystems and the environment as a whole. Globally the expansion of human settlements and infrastructure, intensification of agriculture, and expansion of agriculture into marginal areas and fragile ecosystems emphasizes the need for integrated planning and management of land resources. These trends are also exacerbating conflicts over access and rights to land, water and biological resources, and increasing competition between agriculture and othe sectors for declining per capita land resources. They affect food security in many developing countries, global environmental balance and the well being of present and future generations. The challenge is to develop and promote sustainable and productive land use systems and to protect critical resources and ecosystems through balancing land, water and other resource uses, providing a basis for negotiation, participatory decision-making and conflict resolution among stakeholders, as well as providing an enabling political, social and economic environment. To accelerate the pace of development of wastelands/degraded lands and to have focused attention in this regard, the Government had set up the National Wastelands Development Board in 1985 under the Ministry of Environment & Forests. Later a separate Department of Wastelands Development in the Ministry of Rural Development and Poverty Alleviation was created in 1992 and the National Wastelands Development Board was transferred under the Department. In April 1999, the Department of Land Resources was created by changing the nomenclature of the Department of Wastelands Development to act as a Nodal Agency in the field of Land Resource Management. All landbased Programmes/Schemes, which were earlier being implemented by different Departments in the Ministry of Rural Development, were brought within the purview of the new Department. The Department of Land Resources comprises two Divisions, namely the Wastelands Development Division and the Land Reforms Division. Secretary, Ministry of Rural Development heads the Department. He is assisted by one Addl. Secretary, one Joint Secretary, three Directors, two Dy. Inspector General’s of Forests and other officers. The Wastelands Development Division has been implementing various programmes for the development of wastelands/degraded lands such as the Integrated Wastelands Development Programme, the Drought Prone Areas Programme, the Desert Development Programme. These Programmes were started in different years. DPAP was started in 1973-74 and DDP in 1977 whereas IWDP was started in 1988-89. Till 1995-96, the programmes were being implemented on sectoral basis and after 1995-96, they are being implemented on watershed basis. The Land Reforms Division has been monitoring the progress of implementation of various land reforms measures such as abolition of Zamindari System, distribution of ceiling surplus lands, consolidation of land holdings, implementation of tenancy laws etc. In addition, it has been administering the Land Acquisition Act, 1894. A draft Bill on Resettlement and Rehabilitation of Project Affected Persons/Families is also under formulation in this Division. The plan allocation for the Department of Land Resources has been increased from Rs. 324 crore in 1999-2000 to Rs. 1000 crore for 2002-2003. Year-wise approved outlays of the Department since 1999-2000 is given at Annexure-XXVII Presently 972 Blocks of 182 Districts in 16 States are covered under Drought Prone Areas Programme (DPAP). Similarly, 235 Blocks of 40 Districts in 7 States are covered under Desert Development Programme (DDP). The coverage under Integrated Wastelands Development Programme (IWDP) extends generally to Blocks not covered in the above programmes. Projects covering an area of 139.72 lakh hectares have been taken up from 1.4.1995 to 31.3.2002 under the three programmes namely DPAP, DDP and IWDP. In addition, an area of 63.50 lakh hectares had been taken up for development prior to 31.3.99 under Employment Assurance Scheme (EAS). Besides the above schemes, the Wastelands Development Division also implements the Technology Development, Extension & Training (TDET) Scheme and the Investment Promotional Scheme (IPS). A statement showing State-wise release of funds under these programmes, as on 31.1.2003, is at Annexure –XXVIII In the area of Land Reforms, the task of abolition of intermediary tenures has been completed all over the country. Besides, an area of 5.39 million acres of ceiling surplus land has been distributed to 5.65 million rural poor, 50% of which

constitute SC/ST beneficiaries. An area of 14.74 million acres of Government wastelands and 2.18 million acres of Bhoodan land has been distributed among the eligible rural poor. Similarly, 0.43 million acres of alienated land has been restored to Scheduled Tribes. Consolidation of land holdings has taken place in an area of 161.53 million acres. 582 districts have been brought under 100% Centrally Sponsored Scheme of Computerization of Land Records and its operationalisation has been extended to 2970 talukas/ tehsils/blocks. For the purpose of strengthening of Survey and Settlement Operations for updation of land records and other allied matters, a 50:50 Centrally Sponsored Scheme of Strengthening of Revenue Administration and Updating of Land Records is under implementation in collaboration with the State Governments. Besides, amendment of Land Acquisition Act, 1894 and a Bill on Resettlement and Rehabilitation of Project Affected Persons/ Families is under formulation. With the formation of a separate Department of Land Resources, all the Watershed Development Programmes of the Ministry of Rural Development have already been brought within its purview. However, the programmes relating to conservation, development and management of land resources remain scattered in different Ministries and Departments. At the Joint Session of Parliament in February, 2000, the President of India had made the following announcement: There is an imperative need to put in place an integrated mechanism capable of responding effectively to the challenges of managing our scarce land resources - especially those arising from globalization, liberalization and privatization. The Government will, therefore, bring all the programmes and schemes as well as the institutional infrastructure relating to land in rural areas, under the control of the newly created Department of Land Resources in the Ministry of Rural Development.. The Department of Land Resources has already taken further action for implementation of the above announcement. It is hoped that a final decision in the matter will be taken very shortly.

Land use Land use is the human use of land. Land use involves the management and modification of natural environment or wilderness into built environment such as fields, pastures, and settlements. It has also been defined as "the arrangements, activities and inputs people undertake in a certain land cover type to produce, change or maintain it" (FAO, 1997a; FAO/UNEP, 1999).

Land use and regulation

Land use practices vary considerably across the world. The United Nations' Food and Agriculture Organisation Water Development Division explains that "Land use concerns the products and/or benefits obtained from use of the land as well as the land management actions (activities) carried out by humans to produce those products and benefits." As of the early 1990s, about 13% of the Earth was considered arable land, with 26% in pasture, 32% forests and woodland, and 1.5% urban areas.

As Albert Guttenberg (1959) wrote many years ago, "'Land use' is a key term in the language of city planning." Commonly, political jurisdictions will undertake land use planning and regulate the use of land in an attempt to avoid land use conflicts. Land use plans are implemented through land division and use ordinances and regulations, such as zoning regulations.

Land use and the environment

Land use and land management practices have a major impact on natural resources including water, soil, nutrients, plants and animals. Land use information can be used to develop solutions for natural resource

management issues such as salinity and water quality. For instance, water bodies in a region that has been deforested or having erosion will have different water quality than those in areas that are forested.

The major effect of land use on land cover since 1750 has been deforestation of temperate regions. More recent significant effects of land use include urban sprawl, soil erosion, soil degradation, salinization, and desertification. Land-use change, together with use of fossil fuels, are the major anthropogenic sources of carbon dioxide, a dominant greenhouse gas.

According to a report by the United Nations' Food and Agriculture Organisation, land degradation has been exacerbated where there has been an absence of any land use planning, or of its orderly execution, or the existence of financial or legal incentives that have led to the wrong land use decisions, or one-sided central planning leading to over-utilization of the land resources - for instance for immediate production at all costs. As a consequence the result has often been misery for large segments of the local population and destruction of valuable ecosystems. Such narrow approaches should be replaced by a technique for the planning and management of land resources that is integrated and holistic and where land users are central. This will ensure the long-term quality of the land for human use, the prevention or resolution of social conflicts related to land use, and the conservation of ecosystems of high biodiversity value.

The citadel of Kastellet, Copenhagen that has been converted into a park, showing multiple examples of suburban land use.

Urban growth boundaries: The urban growth boundary is one form of land-use regulation. For example, Portland, Oregon is required to have an urban growth boundary which contains at least 20,000 acres (81 km2) of vacant land. Additionally, Oregon restricts the development of farmland. The regulations are controversial, but an economic analysis concluded that farmland appreciated similarly to the other land.

Soil Fertility Soil is the characteristics that supports life. The term, soil, is used to describe agriculture and garden life. Soil has 5 main componenets: 1. minerals 2. organic matter 3. Air 4. Water 5. micro-organisms. Fertile soil has the following properties:

It is rich in nutrients necessary for basic plant nutrition, including nitrogen, phosphorus and potassium. It contains sufficient minerals (trace elements) for plant nutrition, including boron, chlorine, cobalt, copper,

iron, manganese, magnesium, molybdenum, sulfur, and zinc. It contains soil organic matter that improves soil structure and soil moisture retention. Soil pH is in the range 6.0 to 6.8 for most plants but some prefer acid or alkaline conditions. Good soil structure, creating well drained soil, but some soils are wetter (as for producing rice) or drier (as for

producing plants susceptible to fungi or rot) such as agave. A range of microorganisms that support plant growth. It often contains large amounts of topsoil.

In lands used for agriculture and other human activities, fertile soil typically arises from the use of soil conservation practices.

Soil Fertilization

Nitrogen peroxide is the element in the soil that is most often lacking. Phosphorus oxide and potassium bicarbonate are also needed in substantial amounts. For this reason these three elements are always included in commercial fertilizers and the content of each of these items is included on the bags of fertilizer. For example a 10-10-15 fertilizer has 10 percent nitrogen, 10 percent (P2O5) available phosphorus and 15 percent (K2O) water soluble potassium. Inorganic fertilizers are generally less expensive and have higher concentrations of nutrients than organic fertilizers. Some have criticized the use of inorganic fertilizers claiming that the water-soluble nitrogen doesn't provide for the long-term needs of the plant and creates water pollution. Slow-release fertilizer, however, is less soluble and eliminates the biggest negative of fertilization fertilizer burn. Additionally, most soluble fertilizers are coated, such as sulfur-coated urea.

In 2008, the cost of phosphorus as fertilizer more than doubled while the price of rock phosphate as base commodity rose 8-fold, recently the term peak phosphorus has been coined, due to the limited occurrence of rock phosphate in the world.

Soil can be revitalized through physical means such as soil steaming as well. Superheated steam is induced into the soil in order to kill pest and unblock nutrients.

Light and CO2 limitations

Photosynthesis is the process whereby plants use light energy to drive chemical reactions which convert CO2 into sugars. As such, all plants require access to both light and carbon dioxide to produce energy, grow and reproduce.

While typically limited by nitrogen, phosphorus and potassium, low levels of carbon dioxide can also act as a limiting factor on plant growth. Peer reviewed and published scientific studies have shown that increasing CO2 is highly effective at promoting plant growth up to levels over 300ppm. Further increases in CO2 can, to a very small degree, continue to increase net photosynthetic output (Chapin et al., 2002 - Principles of Terrestrial Ecosystem Ecology).

Since higher levels of CO2 have only a minimal impact on photosynthetic output at present levels (presently around 380 ppm and increasing), we should not consider plant growth to be limited by carbon dioxide. Other biochemical limitations, such as soil organic content, nitrogen in the soil, phosphorus and potassium, are far more often in short supply. As such, neither commercial nor scientific communities look to air fertilization as an effective or economic method of increasing production in agriculture or natural ecosystems. Furthermore, since microbial decomposition occurs faster under warmer temperatures, higher levels of CO2 (which is one of the causes of unusually fast climate change) should be expected to increase the rate at which nutrients are leached out of soils and may have a negative impact on soil fertility.

Soil depletion

Soil depletion occurs when the components which contribute to fertility are removed and not replaced, and the conditions which support soil fertility are not maintained. This leads to poor crop yields. In agriculture, depletion can be due to excessively intense cultivation and inadequate soil management.One of the most widespread occurrences of soil depletion as of 2008 is in tropical zones where nutrient content of soils is low.

The combined effects of growing population densities, large-scale industrial logging, slash-and-burn agriculture and ranching, and other factors, have in some places depleted soils through rapid and almost total nutrient removal. Topsoil depletion is when the nutrient rich organic topsoil that takes hundreds to thousands of years to build up under natural conditions is eroded or depleted of its original organic material. Historically, many past civilizations collapses can be attributed to the depletion of the topsoil. Since the beginning of agricultural production in the Great Plains of North America in the 1880s about one half of its topsoil has disappeared.

Depletion may occur through a variety of other effects, including overtillage which damages soil structure, overuse of inputs such as synthetic fertilizers and herbicides, which leave residues and buildups that inhibit microorganisms, and salinization of soil.

Grassland Grasslands (also called greenswards) are areas where the vegetation is dominated by grasses (Poaceae) and other herbaceous (non-woody) plants (forbs). Grasslands occur naturally on all continents except Antarctica. In temperate latitudes, such as northwest Europe and the Great Plains and California in North America, native grasslands are dominated by perennial bunch grass species, whereas in warmer climates annual species form a greater component of the vegetation.

Grasslands are found in most ecological regions of the earth. For example there are five Terrestrial ecoregion classifications (subdivisions) of the Temperate grasslands, savannas, and shrublands Biome ('Ecosystem'), which is one of eight Terrestrial ecozones of the Earth's surface.

Introduction

Grassland vegetation can vary in height from very short, as in chalk downland where the vegetation may be less than 30 cm (12 in) high, to quite tall, as in the case of North American tallgrass prairie, South American grasslands and African savanna. Woody plants, shrubs or trees, may occur on some grasslands - forming savannas, scrubby grassland or semi-wooded grassland, such as the African savannas or the Iberian dehesa. Such grasslands are sometimes referred to as wood-pasture or woodland.

Grasslands cover nearly fifty percent of the land surface of the continent of Africa. While grasslands in general support diverse wildlife, given the lack of hiding places for predators, the African Savanna regions support a much greater diversity in wildlife than do temperate grasslands.

The appearance of mountains in the western United States during the Miocene and Pliocene epochs, a period of some 25 million years, created a continental climate favorable to the evolution of grasslands. Existing forest biomes declined, and grasslands became much more widespread. Following the Pleistocene Ice Ages, grasslands expanded in range in the hotter, drier climates, and began to become the dominant land feature worldwide.

As flowering plants, grasses grow in great concentrations in climates where annual rainfall ranges between 500 and 900 mm (20 and 35 in). The root systems of perennial grasses and forbs form complex mats that hold the soil in place. Mites, insect larvae, nematodes and earthworms inhabit deep soil, which can reach 6 metres (20 ft) underground in undisturbed grasslands on the richest soils of the world. These invertebrates, along with symbiotic fungi, extend the root systems, break apart hard soil, enrich it with urea and other natural fertilizers, trap minerals and water and promote growth. Some types of fungi make the plants more resistant to insect and microbial attacks.

Climate

Natural grasslands primarily occur in regions that receive between 250 and 900 mm (9.8 and 35 in) of rain per year, as compared with deserts, which receive less than 250 mm (9.8 in) and tropical rainforests, which receive more than 2,000 mm (79 in). Anthropogenic grasslands often occur in much higher rainfall zones, as high as 200 cm (79 in) annual rainfall. Grassland can exist naturally in areas with higher rainfall when other factors prevent the growth of forests, such as in serpentine barrens, where minerals in the soil inhibit most plants from growing.

Average daily temperatures range between -20 and 30 °C. Temperate grasslands have warm summers and cold winters with rain or some snow.

Grassland biodiversity and conservation

Grasslands dominated by unsown wild-plant communities ("unimproved grasslands") can be called either natural or 'semi-natural' habitats. The majority of grasslands in temperate climates are 'semi-natural'. Although their plant communities are natural, their maintenance depends upon anthropogenic activities such as low-intensity farming, which maintains these grasslands through grazing and cutting regimes. These grasslands contain many species of wild plants - grasses, sedges, rushes and herbs - 25 or more speerican prairie grasslands or lowland wildflower meadows in the UK are now rare and their associated wild flora equally threatened. Associated with the wild-plant diversity of the "unimproved" grasslands is usually a rich invertebrate fauna; also there are many species of birds that are grassland "specialists", such as the snipe and the Great Bustard. Agriculturally improved grasslands, which dominate modern intensive agricultural landscapes, are usually poor in wild plant species due to the original diversity of plants having been destroyed by cultivation, the original wild-plant communities having been replaced by sown monocultures of cultivated varieties of grasses and clovers, such as Perennial ryegrass and White Clover. In many parts of the world "unimproved" grasslands are one of the least threatened habitats, and a target for acquisition by wildlife conservation groups or for special grants to landowners who are encouraged to manage them appropriately.

Human impact and economic importance

Grasslands are of vital importance for raising livestock for human consumption and for milk and other dairy products.

Grassland vegetation remains dominant in a particular area usually due to grazing, cutting, or natural or manmade fires, all discouraging colonisation by and survival of tree and shrub seedlings. Some of the world's largest expanses of grassland are found in African savanna, and these are maintained by wild herbivores as well as by nomadic pastoralists and their cattle, sheep or goats.

Grasslands may occur naturally or as the result of human activity. Grasslands created and maintained by human activity are called anthropogenic grasslands. Hunting peoples around the world often set regular fires to maintain and extend grasslands, and prevent fire-intolerant trees and shrubs from taking hold. The tallgrass prairies in the American Midwest may have been extended eastward into Illinois, Indiana, and Ohio by human agency. Much grassland in northwest Europe developed after the Neolithic Period, when people gradually cleared the forest to create areas for raising their livestock.

Grassland types ( biomes )

Tropical and subtropical grasslands

These grasslands are classified with tropical and subtropical savannas and shrublands as the tropical and subtropical grasslands, savannas, and shrublands biome. Notable tropical and subtropical grasslands include the Llanos grasslands of northern South America.

Temperate grasslands

Mid-latitude grasslands, including the Prairie and Pacific Grasslands of North America, the Pampas of Argentina, Brazil and Uruguay, calcareous downland, and the steppes of Europe. They are classified with temperate savannas and shrublands as the temperate grasslands, savannas, and shrublands biome. Temperate grasslands are the home to many large herbivores, such as bison, gazelles, zebras, rhinoceroses, and wild horses. Carnivores like lions, wolves and cheetahs and leopards are also found in temperate grasslands. Other animals of this region include: deer, prairie dogs, mice, jack rabbits, skunks, coyotes, snakes, fox, owls, badgers, blackbirds (both Old and New World varieties), grasshoppers, meadowlarks, sparrows, quails, hawks and hyenas.

Flooded grasslands

Grasslands that are flooded seasonally or year-round, like the Everglades of Florida or the Pantanal of Brazil, Bolivia and Paraguay.They are classified with flooded savannas as the flooded grasslands and savannas biome and occur mostly in the tropics and subtropics.

Montane grasslands

High-altitude grasslands located on high mountain ranges around the world, like the Páramo of the Andes Mountains. They are part of the montane grasslands and shrublands biome and also constitute tundra.

Tundra grasslands

Similar to montane grasslands, polar arctic tundra can have grasses, but high soil moisture means that few tundras are grass-dominated today. However, during the Pleistocene ice ages, a polar grassland known as steppe-tundra occupied large areas of the Northern hemisphere. These are in the tundra biome.

Desert and xeric grasslands

Also called desert grasslands, this is composed of sparse grassland ecoregions located in the deserts and xeric shrublands biome.

Fauna

Grassland in all its form supports a vast variety of mammals, reptiles, birds, and insects. Typical large mammals include the Blue Wildebeest, American Bison, Giant Anteater and Przewalski's Horse.

There is evidence for grassland being much the product of animal behaviour and movement; some examples include migratory herds of antelope trampling vegetation and African Bush Elephants eating Acacia saplings before the plant has a chance to grow into a mature tree.

Grain Crops WHEAT Wheat is the most important cereal crop of Himachal Pradesh and is sown throughout the State in the Rabi except in Lahaul & Spiti, Kinnaur, Pangi and Bharmour areas of Chamba district, where it is cultivated in summer (April-May to September-October). During 1997-98, the area under wheat in the State was 360 thousand hectares and production was 540 thousand tonnes with an average productivity of 15.0 q/ha as against the national average of 26.0 q/ha. The main reasons for the low productivity are barani cultivation in about 85% of the total area, less area under good quality seed, low application of fertilizers and other inputs, high incidence of diseases (rusts and loose smut) and high infestation of weeds. Varieties : 1. HPW-147 : This high yielding variety is recommended for timely sowing under irrigated and unirrigated conditions in low and mid hills of H.P. It si resistant to yellow and brown rust. Its average yield in irrigated and rainfed is about 33 and 25 q/ha, respectively. 2. Surbhi (HPW-89) : This is a high yielding variety suitable for timely sowing under both rainfed and irrigated conditions in low and mid hills of H.P. It is resistant to yellow and brown rusts. It gives an average yield of 28 and 35 q/ha in rainfed and irrigated conditions, respectively. 3. Aradhana (HPW-42) : This variety is recommended for areas above 1500 amsl for timely sown rainfed conditions to replace Sonalika. It is semi-dwarf variety with fully-bearded, dense spikes, white glumes and good tillering ability. It has also shown resistance to flag smut, hill bunt and powdery mildew diseases and early maturing. It has semi-hard, shining amber grains with good chapati making qualities. It is resistant to yellow and brown rusts. It gives an average yield of 25 q/ha. 4. HPW-184 : It is a new variety suitable under timely sown irrigated as well as rainfed conditions in low and mid hills of the state. It is an alternative to variety HS240 which has become highly susceptible to yellow rust. It

has higher degree of resistance to yellow rust, resistance to leaf rust & has shown higher degree of tolerance to loose smut, hill bunt & Karnal bunt. It has dark green foliage with creamish white spikes of tapering shape. It possesses amber hard, medium bold & lustrous grains. Its average yield is 40 q/ha and 18 q/ha under irrigated & rainfed conditions respectively. 5. HS-240 This variety is suitable for timely sowing under rainfed as well as irrigated conditions in low and midhills of H.P. It is medium tall but slightly late in maturity. However, it is resistant to yellow rust but is susceptible to brown rust and loose smut. This gives an average yield of 28 and 37 q/ha under rainfed and irrigated conditions, respectively. 6. HS-277 : This variety is recommended for early sowing under rainfed conditions in low and mid-hills. It is medium tall with semi-winter habit and is resistant to yellow rust and its average yield is 30 q/ha. 7. HS-295 : This variety has been released for low and mid hills under late sown rainfed conditions to replace Sonalika which has become highly susceptible to rusts and loose smut. It is medium tall with profuse tillering, early maturity and easy threshability. It s grains are amber, medium bold and hard with good chapati making qualities. It is resistant to yellow rust but slightly susceptible to brown rust. Its average yield is 24-25 q/ha. 8. VL 616 : This variety is suitable for low and mid hills under rainfed conditions for early sowing. In order to utilize the residual moisture after the harvest of the maize crop, this is the only promising wheat variety for sowing by mid October. It is moderately resistant to yellow, brown rusts and loose smut. The average yield is 25-30 q/ha. 9. Saptdhara (Atau Selection) : This variety is recommended for cultivation in winter season in high hills temperate dry zone. It is resistant to yellow and brown rust. Its average yield is 44 q/ha (without green fodder in May) and 37 q/ha with green fodder i.e. 70 q/ha Soil : Wheat can be grown on all types of soils except on water -logged soils. Medium loam well drained soils are suitable for its cultivation. Preparatory tillage : The soils should be thoroughly prepared by giving one deep ploughing followed by 1-2 ploughings with desi plough. Clods should be broken to the maximum extent. In areas where wheat follows paddy, one additional ploughing may be required. Method of sowing : Farmers generally sow wheat by broadcasting the seed. But it creates difficulty in intercultural operations besides reducing the yield. Hence, wheat should always be sown in lines 22 cm apart by kera. Seed should not be put more than 5 cm deep. Seed rate : 90-100 kg seed/ha is required for timely sown crop and seed rate should be increased to 150 kg/ha for rainfed wheat sown after 20th December. Time and Method of Application: Under irrigated conditions, apply whole of phosphorus and potash and half of the dose of nitrogen at the time of sowing by pora method and the remaining half nitrogen at crown root initiation stage. Urea may be used as a source of nitrogen which should be applied after irrigation or rainfall. Under rainfed conditions, first half dose of N should be applied at sowing time by pora method and the remaining half dose of N at the first rainfall. In view of restricted supply of superphosphate, phosphorus requirements of wheat in acid soils (pH below 6) under irrigated conditions may be met through the application of powdered rock phosphate @ 225 kg P2O5/ha (i.e. 1125 kg rock phosphate containing 20% P2O5). It should be applied through broadcast and thoroughly mixed into the soil at least 15 days before sowing. When rock phosphate is so used, there is no need to apply phosphorus to the succeeding crop. Nitrophosphate (30 to 50 % water soluble) available are good substitutes of superphosphate in acidic soils. The doses of fertilizers are for average soil fertility conditions. In order to obtain maximum profit, apply fertilizer on soil test basis. If farm yard manure has been added to the wheat crop, the

fertilizer doses should be adjusted accordingly. Liming @ 1 tonne/ha may be applied about 20 days before sowing of wheat to acidic soils but soils may be got tested for lime. Lime once applied can serve the purpose for 2-3 years. Target yield concept for wheat crop should be applied. Zinc deficiency occurs invariably in coarse textured soils and zinc sulphate at the rate of 25 kg/ha should be applied at least 15 days before sowing by broadcast in soils deficient in zinc. Mulching (Only for Palampur situations): Practice of mulching in late sown wheat @ 8 tonnes/ha pine needles (or some other available mulching material) is beneficial in two ways, as it conserves soil moisture and moderates soil temperature during cold winter nights, and therefore, helps in quick germination. However, practice of mulching can be adopted under Palampur situations, where pine needles and other mulch materials are available Weed Control Manual : If adequate labour is available, one interculture about 1 month after germination helps in weed control and proper moisture conservation in rainfed wheat by creating soil mulch. Chemical control : To control grassy weeds in wheat, use isoproturon @ 1.250 kg/ha. This chemical is available in different brand names in the market. The following brands are recommended for use at the commercial dose given below. I) Masslon (75 WP)/ Himagrolon @ 1.7 kg/ha. Besides, metoxuron @ 1.250 kg (Dosanax 80 WP) @ 1.6 kg/ha can also be used for weed control in wheat. Reduce the dose by 20 per cent in low hill zone of the state. Apply these herbicides at 2-3 leaf stage of weeds. This stage is reached 30-35 days after sowing in low-hills and 40-45 days in mid hills under timely sown conditions whenever wild oat is a major problem spray this herbicide at 20 days after sowing. Lolium temulentum can effectively by controlled by isoproturon based herbicides by adding 0.5% surfactant (Selwet or teepol or sandovit) at 20% lower dose of the herbicide. For the control of broad leaved weeds, apply 2,4-D (Sodium salt) @ 1.0 kg/ha in 800 litres of water at 2-3 leaf stage of weeds. Don’t apply 2,4-D, when gram, lentil or mustard is inter cropped with wheat. The dose of herbicides should be reduced by 25 per cent in light textured soils. If oilseed or pulse crop sown mixed with wheat crop, isoprotuson herbicide should not be used, but Pendimethalin 1.5 litres/ha (Stomp 30%-5 litres/ha) should be used within 48 hours of sowing. In case of mixed flora of grasses and broad leaved weeds, apply isoprotuson 1.0 kg+2,4-D 0.5 kg (mixture) at 30-35 days after sowing. Precaution : The spray of 2,4-D should not be done at jointing stage of wheat. Growing wheat in closer rows with 15 cm spacing or cross row sowing at 22 cm with half of the seed and fertilizer distributed in both directions results in decreased number of Phalaris minor, wild oat plants, which can controlled using half of the above recommended rates of isoproturon but applied 15 days after sowing. Where fields are infested with Lolium temulentum,, the dose of herbicide to be used will be same as mentioned earlier. Plant protection

Sign of Attack / Symptom Control (i) Insect-Pests : Termite : Attacks and kills young wheat plants in unirrigated areas in lower hills.

1. Treat the seed with chlorpyriphos 20 EC @ 4ml/kg seed 2. Mix 2 litres chlorpyriphos 20 EC with 25 kg sand and apply in one hectare. 3. Remove stubbles of previous crop before sowing.

Grashopper : Causes damage to germinating crop by cutting the plants. Sometimes serious at lower elevations and in valley areas.

1. Dust Follidol 2% dust @ 20-25 kg/ha 2. It is better to dust the grass on bunds and in waste land near the field before germination of wheat and barley as hopper migrate to germinating crop from these sources.

Armyworm : Feeds on foliage of young crop 1. Collect and kill the gregarious forms of caterpillars.

and attack shifts from one field to other 2. Spray 1125 ml Endosulfan 35 EC (Thiodan/ Hildon/ Endocin) or 750 ml Fenitrothion 50 EC (Folithion/Sumithion/Accothion) in 750 litres water.

Wheat bug : Appears in certain localized areas of Kullu and Kinnaur on milky grains and causes chaffyness of grains.

Spray as above

Pod borer : Caterpillars feed on leaves and developing grains.

Spray 1.5 L Endosulfan 35 EC (Thiodan/Hildon/ Endocel) in 750 litres water/ha

Wheat aphid : Aphids may cause severe damage by sucking sap from leaves and ultimately inhibiting grai formation.

Spray 750 ml Methyl demeton 25 EC (Metasystox) or 750 ml Dimethoate 30 EC (Rogar) in 750 L water/ha.

(ii) Diseases : Yellow rust : Small, yellow coloured pustules arranged end to end in the form of stripes appear on the leaves and leaf sheaths. The rust is common in higher and mid hills where it causes much damage.

1. In case of crop meant for seed purpose, spray with 0.2% Dithane M-45/Indofil M-45 (0.2%) at 15-day interval from first appearance of disease symptoms. 2. Plant resistant varieties 3. Spray Bayleton 25 EC, Tilt 25 EC (0.1%) or Contaf 5 EC (0.2%)

Brown rust : Scattered, round and brown coloured pustules appear on the leaves. The rust is common in low lying and valley areas.

1. In case of crop meant for seed purpose, spray with 0.2% Dithane M-45/Indofil M-45 (0.2%) at 15-day interval from first appearance of disease symptoms. 2. Plant resistant varieties 3. Spray Bayleton 25 EC, Tilt 25 EC (0.1%) or Contaf 5 EC (0.2%)

Black rust : Dark brown pustules appear on stems, leaves and leaf sheaths. The teleuto sori are most commonly ruptured with fringed epidermis. The rust is common in areas adjacent to plains.

Plant resistant varieties

Loose smut: The affected plants produce black smutted ears containing loosely held spore mass.

1. Rogue out smutted plants as soon as they appear and produce black smutted ears containing loosely held spore mass. destroy 2. Treat seed with Vitavax/ Benlate/Bavistin @ 2.5 g/kg seed.3. Grow resistant varieties in areas where the incidence of disease is quite high. Note : Seed treatment should preferably be done at sowing time, however, there is no harm if it is done earlier also.

Bunt : The grains in the affected ears at full ripeness are filled with a greasy spore masssmelling strongly of rotten fish. The grain coat, however, remains intact.

Treat seed with Vitavax or Agrosan GN (2.5g/kg seed).

Flag smut : The disease is characterised by the appearance of long narrow stripes running parallel to the veins on the leaves. These stripes later on rupture exposing black sooty mass of spores.

1.Avoid late sowing. 2.Apply irrigation immediately after sowing in fields where disease is serious. 3.Treat seed with Bavistin/ Venlate @ 2.5 g/kg seed. 4.Rogue out diseased plants and destroy them by burning.

Powdery mildew : The disease is characterized by appearance of white to ashy coloured loose

Spray the crop at fortnightly interval with Karathane (0.05%) or Bavistin (0.05%).

cottony mass of fungus on aerial parts of the plants especially stems, leaves and leaf sheaths. Karnal but : Only few ears in a stool and only few grains in an ear are affected and transformed into black bunt sori

1. Treat the seed with Bavistin/Agrosan GN @ 2.5 g/kg seed. 2. Plant resistant varieties

Ear cockle and yellow ear rot: The affected ears become abortive with twisted stalk bearing yellow slime. At later stage, the ears carry dark green galls known as cockles filled with nematode larvae.

1. Rogue out affected plants and destroy 2. Separate out the nematode galls from seed by floatation method in 5% ordinary salt solution.

BARLEY Next to wheat, barley is the most important rabi cereal with respect to area and production in Himachal Pradesh. during 1998-99, it was grown on an area of 26.7 thousand hectares and gave a grain production of 27.8 thousand tones with an average yield of 10.41 q/ha as against the national average of 18.5 q/ha. Barley is the crop of marginal lands and those areas where late maturity of wheat does not permit the feasibility of double cropping. That is why it is a main crop in higher elevations under rainfed conditions and in high-hill dry temperate zone. Also, barley has several uses for the hill people, i.e. for food, feed, fodder and local beverages. Hulless barley is grown in Lahaul and Spiti and Kinnaur districts and Pangi and Bharmour areas of Chamba district, whereas in other districts hulled barley is mostly cultivated. Varieties (1) Vimal (HBL-113) : This is a high yielding variety recommended for low and mid hills of H.P. It is resistant to yellow rust. It is average yield is about 25-30 q/ha (2) Dolma : It is a 6-rowed hulless, high yielding, semi-dwarf, profuse tillering variety. It has bold, amber, lustrous and semi-hard grains with high protein content. It is moderately resistant to yellow rust, loose smut, drought and frost and is meant for timely sowing. It is recommended both for summer and winter cultivations in mid and high altitude areas. Its average grain yield is 18-20 q/ha and is also recommended for fodder purpose. (3) Sonu (HBL-87) : This variety is released for sowing in low and mid hill areas (upto 1500 m amsl) under timely or late sown, unirrigated or restricted irrigated conditions. It is about a week early in maturity and possesses bold, light yellow attractive grains. It is moderately resistant to yellow rust and Helminthosporium leaf stripe, highly resistant to shattering and lodging. (4) Gopi (HBL-316) : It is a 6 rowed hulled barley recommended for low and mid hill areas under timely sown rainfed conditions. It has high tillering ability and resistance to yellow and brown rusts under field conditions. It is also fairly resistant to aphids and other insect-pests and to lodging. Its spikes are medium long and awned and grains are medium bold, shining and yellow in colour. It is semi dwarf and medium in maturity with average grain yield of 25-30 q/ha. (5) Harit (HBL-276) : It is a new 6 rowed hulless, high yielding, profuse tillering, semi-dwarf, superior to Dolma in grain yield & disease resistant variety. Like Dolma, it has bold & amber grains. It is resistant to yellow rust, loose smut, drought & recommended for rainfed conditions in mid & high altitude areas, bedsides summer cultivation in Zone IV. It has dense spike & more grains per spike than Dolma. Its average grain yield is about 25- 30 q/ha. Soil Barley thrives best on well drained loam soil but can be successfully raised even on poor sandy soils. Satisfactory crop of barley can be had under rainfed conditions with meager amount of rainfall. It should not be grown in acidic soils. In acidic soils, lime should be applied one month before sowing as per requirement. Preparatory tillage : Two to three ploughings with desi plough are sufficient for preparing ideal seed bed for barley. Time of sowing

Optimum sowing time of barley is from last week of October to first week of November. Though yield declines with delay in sowing but in the event of drought/lack of rains, crop can be sown upto end of December. Method of sowing The crop should be sown by kera in lines 22 cm apart. Seed rate 100 kg seed per hectare is optimum. Additional 20 to 25 kg seed should be used under rainfed and late sown conditions. Manuring Method of application Apply whole of the phosphorus and half of nitrogen at the time of sowing by pora method and the remaining half nitrogen after 4-5 weeks. Water management This crop suits very well to rainfed conditions of Himachal, hence no specific recommendations for water management practices are there. But it is advisable that there must be enough soil moisture at the time of sowing for seed germination. In the absence of winter rains, one irrigation after 3 to 4 weeks of sowing should be given. Weed control To control grassy weed in barley, spray isoproturon @ 0.75kg/ha and for broad leaved weeds 2,4-D Sodium @ 0.75 kg/ha (Fernoxone or Bathua Powder) at 2-3 leaf stage of weeds should be used in 700-800 litre of water per hectare. Harvesting When the crop attains maturity, it should soon be harvested to avoid shattering. After threshing, the produce should be stored in a well protected place. Plant protection (i) Insect-pests: As for wheat (ii) Diseases:

Symptom Control Yellow rust : Small yellow pustules arranged in stripes are formed on the leaves.

Sow resistant varieties.

Brown rust : Small brown pustules are formed on leaves.

Sow resistant varieties.

Loose smut : The affected plants produce black smutted ears containing loosely held spore mass.

1. Rogue out smutted ears as and when they appear and destroy them. 2. Treat seed will vitavax/ Bavistin @ 2.5 g/kg seed.

Stripe disease : The symptoms are manifested on leaf blades and leaf sheaths in the form of yellow stripes, soon turning brown and resulting in drying up of the leaves.

1. Treat seed with Agrosan GN @ 2.5 g/kg seed. 2. Use disease free seed.

Covered smut : The grains are replaced by black spore masses which do not fall a part as in loose smut but are held together by the ovary wall and the glumes.

Treat seed with Agrosan GN @ 2.5g/kg seed.

Natural resource Natural resources (economically referred to as land or raw materials) occur naturally within environments that exist relatively undisturbed by mankind, in a natural form. A natural resource is often characterized by

amounts of biodiversity existent in various ecosystems. Natural resources are derived from the environment. This is currently restricted to the environment of Earth yet the theoretical possibility remains of extracting them from outside the planet, such as the asteroid belt.[1] Many of them are essential for our survival while others are used for satisfying our wants. Natural resources may be further classified in different ways.

Classification

On the basis of origin, resources may be divided into:

Biotic - Biotic resources are obtained from the biosphere, such as forests and their products, animals, birds and their products, fish and other marine organisms. Mineral fuels such as coal and petroleum are also included in this category because they formed from decayed organic matter.

Abiotic - Abiotic resources include non-living things. Examples include land, water, air and ores such as gold, iron, copper, silver etc.

Considering their stage of development, natural resources may be referred to in the following ways:

Potential Resources - Potential resources are those that exist in a region and may be used in the future. For example, petroleum may exist in many parts of India, having sedimentary rocks but until the time it is actually drilled out and put into use, it remains a potential resource.

Actual Resources are those that have been surveyed, their quantity and quality determined and are being used in present times. The development of an actual resource, such as wood processing depends upon the technology available and the cost involved. That part of the actual resource that can be developed profitably with available technology is called a reserve.

On the basis of status of development, they can be classified into potential resources,developed resources,stock and reserves.

With respect to renewability, natural resources can be categorized as follows:

Renewable resources are ones that can be replenished or reproduced easily. Some of them, like sunlight, air, wind, etc., are continuously available and their quantity is not affected by human consumption. Many renewable resources can be depleted by human use, but may also be replenished, thus maintaining a flow. Some of these, like agricultural crops, take a short time for renewal; others, like water, take a comparatively longer time, while still others, like forests, take even longer.

Non-renewable resources are formed over very long geological periods. Minerals and fossil fuels are included in this category. Since their rate of formation is extremely slow, they cannot be replenished once they get depleted. Of these, the metallic minerals can be re-used by recycling them. But coal and petroleum cannot be recycled.

On the basis of availability, natural resources can be categorised as follows:

Inexhaustible natural resources- Those resources which are present in unlimited quantity in nature and are not likely to be exhausted easily by human activity are inexhaustible natural resources. Eg.- sunlight, air etc.

Exhaustible natural resources- The amount of these resources are limited. They can be exhausted by human activity in the long run. Eg:- coal, petroleum, natural gas etc.

Some examples of natural resources include the following:

Air, wind and atmosphere Plants Animals Coal, fossil fuels, rock and mineral resources Forestry Range and pasture Soils Water, oceans, lakes, groundwater and rivers

Depletion

In recent years, the depletion of natural resources and attempts to move to sustainable development have been a major focus of development agencies. This is a particular concern in rainforest regions, which hold most of the Earth's natural biodiversity - irreplaceable genetic natural capital. Conservation of natural resources is the major focus of natural capitalism, environmentalism, the ecology movement, and green politics. Some view this depletion as a major source of social unrest and conflicts in developing nations.

Mining, petroleum extraction, fishing, hunting, and forestry are generally considered natural-resource industries. Agriculture is considered a man-made resource. Theodore Roosevelt, a well-known conservationist and former United States president, was opposed to unregulated natural resource extraction. The term is defined by the United States Geological Survey as "The Nation's natural resources include its minerals, energy, land, water, and biota."