Saturday, December 20, 2014
Director, Centre for Environmental Studies,
Gitam University, Visakhapatnam
Cloud seeding operations have been successfully conducted by about 40 countries during different periods during the last 50 years. Recently Australia has taken up cloud seeding operations in Snowy Mountains region to augment annual precipitation not only to obtain more snow cover for improving the tourist trade but also for hydropower generation and food production, besides using this technology to fight the emerging impacts of the global warming. China has been extensively using cloud seeding operations by employing more than 35000 people to fight the disastrous consequences of the recurring droughts and also to reduce the summer temperatures and thereby cut down electrical power for air conditioning. Indonesia is conducting cloud seeding operations to store additional water supplies in reservoirs for subsequent use during years of water scarcity and drought. Cloud seeding is used in several places in Russian and American states to eliminate the recurring fog conditions that cause serious traffic disruptions in Airports and major urban settlements. Many countries are extensively using cloud seeding to make drastic reductions in the damages caused to lives and properties due to recurring hail. Presently scientists are considering the revival of cloud seeding experiments to tame the cyclones and thereby mitigate the damage caused by cyclones and hurricanes. Thailand is regularly conducting cloud seeding operations every year to obtain about 2000 mm of annual rainfall not only to meet the municipal, industrial and agricultural needs but also to promote large scale tourist trade by promoting environmental assets like good landscapes, gardens, forests and wild life. In a few places cloud seeding is used to fight the forest fires and to prevent unwanted rainfalls that are likely to disturb the organization of scheduled international celebrations, games and sports.
Cloud seeding is cheaper for water supply than conventional irrigation: A brief review of some of the case studies on cloud seeding experiments conducted in different countries to achieve increased rainfall for municipal water supply, hydropower generation and agricultural production at the cheapest cost are presented here. For more details refer to the relevant websites cited. Further the costs of water supply from various other sources are very high as compared to cloud seeding, which can be seen from the following table-1.
Is artificial rainwater 150 times cheaper than ground water …?
Sandy Land Underground Water Conservation District (SLUWCD) has been working day and night in the interests of the farmers to encourage food production to promote the state economy and for this purpose have chosen the most effective method of increasing the water availability by large scale tapping of the sky water and they have succeeded because of their sincere efforts and close rapport between their scientific and technological experts, administrators and the general public. The target area includes Yoakum, Terry and Gaines county regions in West Texas. http://www.sandylandwater.com/cost_benefit.htm
SOAR (Southern Ogallala Aquifer Rainfall) Programme, Texas cloud seeding project covered 5.048 million acres during the operational seasons covering 77 clouds in 2002 and 69 clouds in 2003. Yoakum county for its 5 lakh acres coverage shared the operational costs estimated at $20,000. Two independent reputed weather consultant agencies evaluated the cloud seeding project results. 63 out of 69 clouds seeded during 2003 season produced rainfall increase of about 2,50,000 ac.ft. For the 77 clouds seeded during 2002 season each cloud system produced additional rainfall upto about 5000 Kton making a total increased rainfall of 3,80,000 Kton or 3,06,740 ac.ft. (One Acre feet =1234 Cubic meters)
However the economics of cloud seeding have been estimated for Yoakum county.
1. Cost benefit ratio for Yoakum county for 2002
a) Yield per acre of the total SOAR project area for 2002 =
(3,06,740 ac.ft) ÷ 5048000acres = 0.06 ac.ft per acre
b) Proportion of excess water for Yoakum county for 2002 =
(0.06 ac.ft/acre) X (511808 acres) = 31,100 ac.ft.
c) Cost per acre ft = ($20,000) ÷ (31,100 ac.ft) = $0.64 /ac.ft.
2. Cost benefit ratio for Yoakum county for 2003
d) Yield per acre of the total SOAR project area for 2003 =
(248500 ac.ft) ÷ 5048000acres = 0.05 ac.ft per acre
e) Proportion of excess water for Yoakum county for 2003 =
(0.05 ac.ft/acre) X (511808 acres) = 25,194 ac.ft.
f) Cost per acre ft = ($20,000) ÷ (25,194 ac.ft) = $0.80 /ac.ft.
The above costs for Yoakum county for 2002-2003 represent the purchasing cost of additional water produced by cloud seeding. But the farmers are normally spending $120 per acre foot in pumping costs from underground water wells. So if we compare the costs of pumping incurred by the farmers with the cost of about $0.80 for cloud seeding operation, the cost benefit ratio comes to 1:150. This clearly shows that for every dollar spent by the farmer in Yoakum county the benefits obtained will be 150 times higher.
Hydro-electricity at cheaper cost :
Tasmania produces most inexpensive hydro-electricity: Tasmanian Hydro-Electric Commission is convinced of the economic success of the Tasmanian experiments. This is perhaps best illustrated by the decision of the Hydroelectric Corporation (HEC) to undertake the Tasmania II experiment without any operational assistance from CSIRO. However, the HEC has retained a very pragmatic approach to cloud seeding. McBoyle (1980) quoting from Watson (1976) states “Cloud seeding has emerged as a feasible and economic proposition in Tasmania when the increase in precipitation can be utilized for power generation”. Currently Searle (1994) estimates that each HEC cloud seeding operation costs $645,000 to run and returned an average 55 mm of extra rain during each 6 months experimental season. When the extra water in storage is priced against the energy generated by the only HEC thermal station the real profit from the silver iodide seeding comes to about $14.5 million per annum (Searle, pers. comm.) Seeding of these cloud systems resulted in a 37% increase in rainfall. Suitable days occurred 18 times a year during the experiment and this gave rise to an estimated total increase of 197 mm for seeded days.
Cost-benefit analyses carried out by the Tasmanian Hydro-Electric Commission for the Tasmanian I experiment suggest that the increased rainfall from seeding represents a gain of 13:1. More recently Searle (1994) argues that the three separate cloud seeding projects sponsored
by the Hydro-Electricity Commission of Tasmania spanning 14 years have confirmed that cloud seeding can routinely enhance runoff into Tasmanian storages by 10-20%. Searle estimates that the energy gained by the cloud seeding operation costs less than 0.2 US cents per kilowatt hour.http://www.dar.csiro.au/publications/cloud.htm#pt2
Gautemala : The Gautemala cloud seeding evaluation was based upon monthly precipitation data for the period 1980 to 1989. The calculated 17 percent increase for the chosen month of 1992 June precipitation over the Chixoy drainage of Gautimala was equivalent to 1.81 inches. The Chixoy drainage is approximately 2,140 square miles or 1,369,837 acres. INDE officials indicated that the Chixoy watershed converts precipitation to runoff with an efficiency of approximately 30 percent. The additional June stream flow into Chixoy as a result of the cloud seeding program can be estimated as follows:
1,369,837 acres x 1.81 inches = 206,617 acre-feet.
With the 30 percent efficiency factor applied, this equals to 61,985 acre-feet (76,427,505 cubic meters). The cost of this program can be pro-rated to estimate the program costs for June 1992. This cost is $79,700 (U.S.). Consequently, the estimated cost of the additional runoff is $1.29 (U.S.) per acre-foot or $0.001 (U.S.) per cubic meter.
Honduras : Cloud seeding was conducted over the El Cajon and Lake Yojoa drainage basins in Honduras during 1993, 1994, 1995 and 1997 rainy seasons, to augment natural precipitation in these drainages, which will then augment the amount of inflow into the El Cajon Reservoir. This extra water can then be released to generate additional hydro-electric power. Evaluations of the 1993, 1994 and 1995 cloud seeding programs indicated a 9 to 15 percent increase in precipitation
attributed to the cloud seeding.
The June through October 1995 program indicated a 13 percent increase. Additional runoff was estimated as 366,876,000m3. Calculations of the cost of the program versus the value of the additional inflow from the 1995 program were performed using certain assumptions. The resultant benefit to cost ratio was calculated to be 23 ½ :1. http://www.nawcinc.com/cseng.PDF
Inexpensive agriculture and drought mitigation :
China uses cloud seeding for several purposes: The ground precipitation enhancement operations in Feng Huang County of Hunan province during 1975-77 showed an increase of 55% of the daily rainfall by statistics. Experiments in rainy season (April to June) during 1975-86 using rockets in Fujian province showed rainfall increase by 24% with significant level of 0.05.
A group of scientists from the Chinese Academy of Sciences concluded after recently doing research in the province that exploiting water resources in the air could be a sustainable way to solve water scarcity in North China. Based on the advice of the scientists, the provincial government of Shanxi has made a six-year plan to develop weather modification technologies, mainly seeding clouds to increase precipitation. The province will strive to increase its annual rainfall by 2 to 3 billion cu m a year. Shanxi is among one of the most arid provinces in China, with about 4 million people and nearly 1 million head of livestock being affected every year.
Dry weather also leads to reduced grain harvest, local officials said. Since the late 1980s, Shanxi
has been seeding clouds to increase precipitation by 600 million to 800 million cu m a year.
According to Qin Dahe of China Meteorological Administration (CMA) cloud seeding operations were conducted from 1995 to 2003 in 23 provinces by using 42321 flights of aircraft with a total flight time of 9881 hours and employed artillery and rockets. The cloud seeding operations covered 30 lakh sq.km and precipitation was 2100 billion cu.m (73,500 TMC). During 2003 alone 3,800 rocket launchers, 7000 anti aircraft guns and many aeroplanes were used in about 1800 counties and employed 35,000 people for the operations. About 413 Yuan (US$49million) were spent for the operations.
According to Zhang Qiang a noted Beijing official, in the first half of 2004, the meteorologists injected silver iodide particles into the clouds to augment rainfall or snowfall over Beijing Aeroplanes, rockets, artillery shells, meteorological balloons and mountain top based generators were employed. From January to end of June (Beijing Time report dt.24-7-2004) China used 227 aircraft putting in 530 hours of flight time in cloud seeding operations in 15 provinces and regions covering an area of about 1.66 million square km and sprinkled chemicals into the clouds by using 12,464 rockets and 66,000 large caliber artillery shells in different provinces and cities producing 10 billion cubic meters (350 TMC) of water. Zhang Qiang estimated that the cost of 1 cu.m of man made rain works out to 2 US cents (equivalent to one Indian rupee).
According to Hu Zhijin a cloud expert with Chinese Academy of Sciences Cloud seeding is cheaper than other methods used by Government to solve the water shortage problem such as the South-North water diversion project intended to transport water from Yangtze river basin to Beijing and Northern parts of China. He said that for one dry season about 2 to 3 million Yuan (US $ 24,180 to $ 36,270) was needed to carry out the cloud seeding programmes.
Pakistan : Qamar-uz-Zaman Chaudhry, Director-General of the Pakistan Meteorological Department (PMD), said that the department was conducting cloud seeding experiments in the country with the assistance of the Army Aviation, which was called artificial rain, though it was somewhat misleading. However, he said, these experiments met with considerable success. He said that PMD initiated the experiments from June 2000 to augment rainfall mainly over drought hit areas of the country. He lamented that at this experimental stage, besides the limitations of resources (equipments, specially equipped aircraft etc) the main reason for limited success in winter was that very weak weather systems were approaching Pakistan. Most of these clouds were lacking the moisture content or these were high clouds it could be developed to a level where drought situations could be averted, he added. He said that among the three experiments -one in Murree area and two in Baluchistan - could achieve some success in the form of rain/snow.
The President of Pakistan, General Musharaff proved his statesmanship as a savior of the people and the environmental assets of Pakistan by directing the Heads of the Pakistan Meteorological Department and the Aviation Department to fight against the recurring droughts by conducting experiments on cloud seeding to promote annual precipitation to augment substantially the snow fall and the rainfall. Pakistan had made a success of the cloud seeding experiments. Out of the 48 warm cloud experiments conducted 30 were highly successful, 14 had a limited success and 4 failed due to technical problems with the aircraft. Out of the 23 cold cloud seeding experiments 9 were highly successful, 6 had limited success and 8 have failed.
Wyoming: On March 19,2002 the Governor’s Drought Management Task Force met in Cheyenne to discuss and evaluate Wyoming’s conditions and drought outlook. During the meeting it was stated that Municipalities, agricultural interests, hydro-electric companies and others that would benefit from additional snow pack that would help cover the costs. Jeri Trebelcock with the Popo Agie Conservation District said the cost of cloud seeding equates to $1 per acre-foot.
Nevada: Benefits vary with the seasonal frequency of suitable weather opportunities. Research results have documented precipitation rate increases of 0.1 - 1.5 millimeters per hour due to ground-based seeding during proper weather conditions. Estimates of augmented water from seeding have varied from 20,000 to 80,000 acre-feet over each of the last ten years. Seasonal percentage increase estimates have varied from 4 to 10%; generally greater in drought years; less in above normal years. The cost of augmented water, based on the cost of the program,has ranged from $7 to about $18 per acre-foot. http://cloudseeding.dri.edu/Program/Synopsis.html
Kansas: Brian Vulgamore, who conducted Kansas-State’s study, said “Unfortunately, science was unable to separate fact from fiction after that, due to lack of research funding in the 1980s and ’90s.” That’s why his study bypassed the science of modifying the weather. Instead, Vulgamore tried to assess real-life impacts. He examined both rainfall and hail in western Kansas and worked to put their outcomes in dollar terms. “The smallest drought causes economic harm in any semi-arid farming region,” Kastens pointed out. “Up to a point, extra rainfall brings extra economic benefits.” But equal precipitation losses and gains don’t bring equal results. Vulgamore’s analyses suggest that an added inch of growing-season rain in western Kansas translates into an economic gain of about $18 million. A 1-inch loss in rainfall translates into economic losses exceeding $19 million.
North Dakota: Sell and Leistritz (1998) studied the economic impacts of cloud seeding in North
Dakota. Eight of North Dakota’s most common crops like wheat, barley, sunflower, soybeans, dry edible beans, corn grain, oats, and flax were evaluated for impacts of a statewide cloud seeding program. Results were based on a 45 percent reduction in crop losses (Smith, et al.,1997), and a 15 percent increase in rainfall (Changnon and Huff, 1972). The annual crop production increase was $34.4 million for hail reduction and $52.2 million for rainfall enhancement statewide.
This $86.6 million direct impact results in an increase in total business activity of $267 million or an average of $14.52 per planted acre. Additionally, the estimated $3.2 million annual cost of operating a cloud seeding program statewide is more than offset by the $5.1 million in increased tax revenues. Thus, the program more than pays for itself. Additional benefits to other crops, livestock and reduction of property damage were not included in this report, but are also thought to be substantial. http://www.swc.state.nd.us/arb/graphics/QandA.pdf
California: The cost of the annual cloud seeding program is shared among the County and the water districts, which receive a benefit from it. The cost is well justified when compared to its benefits. The average cost of water produced by cloud seeding is less than $100 per acre-foot. By comparison, the cost of State Water on the South Coast is roughly $1200 per acre-foot. Desalinated seawater costs approximately $1950 per acre-foot. Groundwater and water from Lake Cachuma average between $75 and $250 per acre-foot. Cloud seeding is one of the least expensive sources of water. (Santa Barbara County,USA).
Municipal water supplies at cheaper cost :
UTAH cloud seeding program: The estimated average annual increase in runoff due to cloud seeding in Utah is 249,600 acre-feet. This is an average annual increase of 13.0 percent. The estimated project cost for the 1999-2000 season is $254,300. The resulting cost per acre-foot is about one dollar ($1.02).http://water.utah.gov/cloudseeding/PDF/Utcsprog.pdf.
Syria : Cloud-seeding technology is generally an expensive process, dependent on its efficiency and effectiveness. The equipment used in Jordan included C-B and VRC 74 weather radars, and an aircraft equipped with meteorological recording instruments. The aircraft also contained a computer, satellite station (METEOSAT NOAA), qualified radar technicians, engineers, meteorologists and pilots. In Syria, the cloud-seeding project was initiated in 1992, involving similar equipment and staff. Six aircraft were used for seeding purposes during 1993-1994, with the project costs reaching 156 million Syrian lira. The operation costs reached 25 million Syrian lira (US$ 0.5 million) in 1998. The costs per cubic meter of water for the years 1991-1997 were previously highlighted. Based on the regression method used to estimate the increased rainfall, the costs range between US 0.026-0.181 cents/m3 of water, and between US 0.016-0.113 cent/m3
if the ratio method is used.
UNEP Programme: It is estimated that the cost of water produced is about $1.50/m3/season/ha (United Nations, 1985). This cost is made up of scientific equipment and hardware costs; flying costs for cloud seeding (capital and operational, including maintenance or hire charges); salaries for scientists and pilots; the cost of seeding agents and flares; and, software costs (for experimental and monitoring purposes).
South Africa: Studies by the hydrological community have projected a ~25% increase in annual
run off in typical Highveld catchments if the annual rainfall could be increased by 7%. If attainable, this will result in additional water at about 1/5 the cost of the cheapest alternative in South Africa.http://metsys.weathersa.co.za/cloud_detail.htm
Experiments on warm clouds by IITM, Pune (1973-1986) : The Indian Institute of Tropical Meteorology, Pune launched a warm cloud seeding experiment using aircraft in the semi-arid region towards East of Pune on the leeward side of the Western ghats from 1973 to 1986. A randomized double area crossover design with a buffer zone was used for the aerial seeding work. The experimental area covering 4800 sq. km. was divided into 3 parts designated as North, Buffer and South sectors in Ahmadnagar, Baramati area (Hindu dated 18-1-1988). The results of experiments on aerial seeding of warm clouds with common salt and soap stone powder for the eleven years. (Refer Warm Cloud Seeding Chapter)
Cost Benefit Ratio For Warm Cloud Seeding : The cost-benefit Ratio for the warm cloud seeding experiment based upon the data collected by the Institute at Pune for the increase in precipitation of about 20% works out as follows:
i) Total cost of the experiment during the past Rs.58.0 lakhs
11 monsoon seasons (Aircraft changes and cost of seeding material)
ii) Expenditure incurred during 1986 Rs. 8.0 lakhs
iii) Cost benefit ratio for a 20% increase in rainfall due to seeding.
Average rainfall in the experimental area during monsoon – 346 mm
Volume of water produced by artificial rain during one monsoon season
Target x Rainfall increase = (16000 x (1000)2 x 346 x 20)/( 1000 x 100)
= 110720 x 103 m3
Cost of producing 1 m3 = (Cost of the experiment ) / (Volume of the water)
1000 liters) of water produced by artificial rain)
= less than 1 paise per 1000 litres of water
Minimum cost of water supplied by = 60 paise per 1000 litres
Municipal /state Government authorities
Cost benefit ratio of artificial rain = 1 : 60
Experiments in Visakhapatnam, 2002 : At the request of the Municipal Corporation of Visakhapatnam Aerial Cloud Seeding was undertaken besides two ground based generators located at Simhachalam hills during 12-14 October 2002. The helicopter used flew for two hours on each day during 1600 to 1800 hours. The seeding was done by sprinkling the Sodium Chloride powder of 200 Kg. on each day manually at heights of about 1 to 1.5 km above the sea level.
The results are reproduced in Fig. 1 to 3 clearly demonstrate the increased rainfall. Assuming the area of the district where 42 out of 43 reported rainfall during seeding as 10,000 sq.km. with district average rainfall of 12th as the baseline, the increased water due to seeded rain is estimated at about 15 TMC. The expenditure involved was only about Rs.6 lakhs which clearly demonstrate the cheapest and viable alternative to increase water resources. http://www.geocities.com/jvmnaidu/watershed.html
From the above studies it may be seen that the cost of cloud seeding varies greatly, depending on a large number of factors, such as which seeding methods and materials are appropriate to a specific application, the frequency of seedable conditions, the size of the intended area of effect and the duration of the project. Most cloud seeding projects carry favorable benefit/cost ratios, ranging over 20:1 in some cases. http://www.nawcinc.com/wmfaq.html .
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- SHIVAJI RAO- ENVIRONMENTALIST
- Born in 1932 at Mudinepalli, near Gudivada, Krishna Dist. Andhra Pradesh, received Bachelors degree in Civil Engg., from Viswesaraiah Engineering College, Banglore (1956) and Masters Degree in Environmental Engineering from Rice university, Houston, Texas, (USA) (1962), Ph.D (Hony). Former Head of the Department of Civil Engineering and principal of College of Engineering, Andhra university.Formerly Hony.Professor in Andhra University,Manonmanian Sundarnar University,JNT University. Fellow of the Institution of Engineers,India Recipient of the University Grants Commissions National Award "Swami Pranavananda Award on Ecology and Environmental Sciences" for the year 1991. Recipient of Sivananda Eminent Citizen Award for 2002 by Sanathana Dharma Charitable Trust, Andhra Pradesh state. Presently Working as Director, centre for Environmental Studies, GITAM University, http://www.geocities.com/prof_shivajirao/resume.html http://www.eoearth.org/contributor/Shivaji.rao