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California Agriculture, Vol. 46, No.6

Water transfers: Who wins? Who loses?
Cover:  Workers line the South Alamo Canal with concrete, a project involving 150 miles of existing earthen lateral and main canals in the Imperial Irrigation District (IID). The lining prevents ground seepage, a conservation measure funded under the historic water transfer agreement between IID and Metropolitan Water District (MWD). It will allow the capture of previously lost water for use by MWD. Photo by Don Harvey, courtesy of IID
November-December 1992
Volume 46, Number 6

Peer-reviewed research and review articles

Conflict within irrigation districts may limit water transfer gains
by Michael D. Rosen
| Full text HTML  | PDF  
The author analyzes three potential district policy responses to a recent water agreement in the Imperial Valley.
This is the first of two articles offering different views on who wins and loses in water trades. The first, by Mike Rosen, analyzes possible effects of three policies by winch irrigation districts might distribute water transfer gains. The second, by Rodney Smith, reinterprets the Rosen data and defends a “negotiated certificates” water trading scheme. FA. The Imperial Irrigation District and the Metropolitan Water District (MWD) of Southern California have recently concluded an agreement which is historic because of its long-term nature and the volume of water to be transferred. Imperial will transfer 106, 110 acre-feet of water to MWD annually for 35 years in exchange for MWD providing funds for Imperial conservation projects. The projects are to be completed by 1994 and paid for by MWD over a 35-year period for a total cost of $222 million. The effective price of water to Metropolitan will be about $100 per acre-foot per year. Proposals for alternative uses for these funds could become a major source of conflict within the Imperial district. Three potential policies are examined in this article. At present, Imperial receives and controls the funds, but the district is contemplating ways to allow district landowners and farm operators to receive funds directly. Water transfers have been promoted as voluntary transactions in which there can be no losers. But decision-making within water districts is collective in nature, and intra-district conflict may arise. Individual members of districts may have reason to oppose transfers, and aggregate benefits may not be realized.
Lessons of the Rosen study: District control of water transfers likely to benefit landowners
by Rodney T. Smith
| Full text HTML  | PDF  
By controlling water trades, districts may negotiate better financial terms than can landowners individually.
Provided that their districts pursue water transfer opportunities in good faith, landowners benefit from district control of water transfers. Rosen's case study suggests that the value of district control may be substantial. But contrary to Rosen's assertion, tenant farmers need not fear economic loss from water transfers.
Imported parasite may help control European asparagus aphid
by Kent M. Daane, Glenn Y. Yokota, Richard F. Gill, Leopoldo E. Caltagirone, Kenneth S. Hagen, Dan Gonzalez, Petr Stary, William E. Chaney
| Full text HTML  | PDF  
Tests indicate that Trioxys brevicornis, a natural enemy of European asparagus aphid acquired from Czechoslovakia, is well suited to California growing conditions.
The parasite Trioxys brevicornis was imported from Czechoslovakia and released in California to help control the European asparagus aphid. Field performance of this parasitic wasp indicates it has potential to become permanently established in California. Aphid parasitism by T. brevicornis was especially good in comparison.
Furrow torpedoes improve irrigation water advance
by Lawrence J. Schwankl, Blaine R. Hanson, Anthanasios Panoras
| Full text HTML  | PDF  
Use of furrow torpedoes improves irrigation uniformity and minimizes water losses.
To increase irrigation uniformity and to reduce drainage volumes, some San Joaquin Valley growers drag weighted steel cylinders (torpedoes) in furrows before irrigation to speed the advance of water across the field. The effectiveness of this practice and the reasons it works have been investigated. At one site, torpedoing reduced the furrow's steady-state water infiltration rate. A similar phenomenon was not observed at the other two sites investigated. An increase in the irrigation advance rate of torpedoed furrows, ranging from 15 to 30%, was noted at each site evaluated. Torpedoed, nonwheel furrows had water advance characteristics similar to wheel furrows. Torpedoing nonwheel furrows therefore resulted in more equal water advance rates among furrows.
Salt deposits in evaporation ponds: an environmental hazard?
by Kenneth K. Tanji, Colin G. H. Ong, Randy A. Dahlgren, Mitchell J. Herbel
| Full text HTML  | PDF  
Some of the minerals that accumulate in evaporation ponds are known to be toxic to waterfowl. But how toxic are the built-up minerals that are eventually removed from dried ponds?
Only one-fifth of the drainage-impacted lands in the San Joaquin Valley's west side discharge their irrigation return flows into the San Joaquin River. One option for the remaining lands is to dispose of drainage waters in evaporation ponds. Eventually, the evaporite salts that form in these ponds must also be removed. In some cases, these evaporites could constitute hazardous wastes.
In laboratory and field tests, water conditioners fail to improve infiltration or prevent clogging
by Jan W. Hopmans, Lawrence J. Schwankl, Stephen R. Grattan, Josh Gravenmier
| Full text HTML  | PDF  
Three physical water conditioners proved ineffective in recent trials.
Three devices that physically treat irrigation water were tested in the laboratory and the field. Results of these experiments indicate these water conditioners were ineffective in increasing the infiltration rate of water into the soil or in preventing calcium carbonate precipitates from clogging drip emitters under the conditions in which they were tested.
Cover crops lower soil surface strength, may improve soil permeability
by Olatunji A. Folorunso, Dennis E. Rolston, P Terry Prichard, Dianne T. Louie
| Full text HTML  | PDF  
Three and five-year studies at two Central Valley sites show that cover crops effects on soil permeability problems vary, depending on the problems cause.
Poor water penetration constitutes a major production constraint for more than 400, 000 acres of agricultural land in California. The associated economic losses are particularly appreciable in the production of fruit and nut crops. In response to a hypothesis that cover crops may improve water infiltration in orchards, studies were conducted at Davis and Ceres. After 3 years' study, results indicate major benefits are possible with the planting of cover crops.
Shorter sprinkler irrigations reduce Botryosphaeria blight of pistachio
by Themis J. Michailides, David P. Morgan, Joseph A. Grant, William H. Olson
| Full text HTML  | PDF  
Both temperature and duration of wetness directly affect infection of pistachio by the fungus.
Botryosphaeria panicle and shoot blight of pistachio caused by the fungus Botryosphaeria dothidea is favored by high temperatures, 80° to 85° F, and wetness periods longer than 12 hours. Based on these requirements, the disease becomes severe in late spring and summer when temperatures increase and after sprinkler irrigations begin. The disease was substantially reduced by shortening sprinkler irrigations from 24 to 12 hours and from 48 to 24 hours in two commercial pistachio orchards in the Sacramento and San Joaquin valleys, respectively.

Editorial, News, Letters and Science Briefs

Lessons from 1991 for a new era of water management
by Henry Vaux, Harold Carter
Full text HTML  | PDF  
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California Agriculture, Vol. 46, No.6

Water transfers: Who wins? Who loses?
Cover:  Workers line the South Alamo Canal with concrete, a project involving 150 miles of existing earthen lateral and main canals in the Imperial Irrigation District (IID). The lining prevents ground seepage, a conservation measure funded under the historic water transfer agreement between IID and Metropolitan Water District (MWD). It will allow the capture of previously lost water for use by MWD. Photo by Don Harvey, courtesy of IID
November-December 1992
Volume 46, Number 6

Peer-reviewed research and review articles

Conflict within irrigation districts may limit water transfer gains
by Michael D. Rosen
| Full text HTML  | PDF  
The author analyzes three potential district policy responses to a recent water agreement in the Imperial Valley.
This is the first of two articles offering different views on who wins and loses in water trades. The first, by Mike Rosen, analyzes possible effects of three policies by winch irrigation districts might distribute water transfer gains. The second, by Rodney Smith, reinterprets the Rosen data and defends a “negotiated certificates” water trading scheme. FA. The Imperial Irrigation District and the Metropolitan Water District (MWD) of Southern California have recently concluded an agreement which is historic because of its long-term nature and the volume of water to be transferred. Imperial will transfer 106, 110 acre-feet of water to MWD annually for 35 years in exchange for MWD providing funds for Imperial conservation projects. The projects are to be completed by 1994 and paid for by MWD over a 35-year period for a total cost of $222 million. The effective price of water to Metropolitan will be about $100 per acre-foot per year. Proposals for alternative uses for these funds could become a major source of conflict within the Imperial district. Three potential policies are examined in this article. At present, Imperial receives and controls the funds, but the district is contemplating ways to allow district landowners and farm operators to receive funds directly. Water transfers have been promoted as voluntary transactions in which there can be no losers. But decision-making within water districts is collective in nature, and intra-district conflict may arise. Individual members of districts may have reason to oppose transfers, and aggregate benefits may not be realized.
Lessons of the Rosen study: District control of water transfers likely to benefit landowners
by Rodney T. Smith
| Full text HTML  | PDF  
By controlling water trades, districts may negotiate better financial terms than can landowners individually.
Provided that their districts pursue water transfer opportunities in good faith, landowners benefit from district control of water transfers. Rosen's case study suggests that the value of district control may be substantial. But contrary to Rosen's assertion, tenant farmers need not fear economic loss from water transfers.
Imported parasite may help control European asparagus aphid
by Kent M. Daane, Glenn Y. Yokota, Richard F. Gill, Leopoldo E. Caltagirone, Kenneth S. Hagen, Dan Gonzalez, Petr Stary, William E. Chaney
| Full text HTML  | PDF  
Tests indicate that Trioxys brevicornis, a natural enemy of European asparagus aphid acquired from Czechoslovakia, is well suited to California growing conditions.
The parasite Trioxys brevicornis was imported from Czechoslovakia and released in California to help control the European asparagus aphid. Field performance of this parasitic wasp indicates it has potential to become permanently established in California. Aphid parasitism by T. brevicornis was especially good in comparison.
Furrow torpedoes improve irrigation water advance
by Lawrence J. Schwankl, Blaine R. Hanson, Anthanasios Panoras
| Full text HTML  | PDF  
Use of furrow torpedoes improves irrigation uniformity and minimizes water losses.
To increase irrigation uniformity and to reduce drainage volumes, some San Joaquin Valley growers drag weighted steel cylinders (torpedoes) in furrows before irrigation to speed the advance of water across the field. The effectiveness of this practice and the reasons it works have been investigated. At one site, torpedoing reduced the furrow's steady-state water infiltration rate. A similar phenomenon was not observed at the other two sites investigated. An increase in the irrigation advance rate of torpedoed furrows, ranging from 15 to 30%, was noted at each site evaluated. Torpedoed, nonwheel furrows had water advance characteristics similar to wheel furrows. Torpedoing nonwheel furrows therefore resulted in more equal water advance rates among furrows.
Salt deposits in evaporation ponds: an environmental hazard?
by Kenneth K. Tanji, Colin G. H. Ong, Randy A. Dahlgren, Mitchell J. Herbel
| Full text HTML  | PDF  
Some of the minerals that accumulate in evaporation ponds are known to be toxic to waterfowl. But how toxic are the built-up minerals that are eventually removed from dried ponds?
Only one-fifth of the drainage-impacted lands in the San Joaquin Valley's west side discharge their irrigation return flows into the San Joaquin River. One option for the remaining lands is to dispose of drainage waters in evaporation ponds. Eventually, the evaporite salts that form in these ponds must also be removed. In some cases, these evaporites could constitute hazardous wastes.
In laboratory and field tests, water conditioners fail to improve infiltration or prevent clogging
by Jan W. Hopmans, Lawrence J. Schwankl, Stephen R. Grattan, Josh Gravenmier
| Full text HTML  | PDF  
Three physical water conditioners proved ineffective in recent trials.
Three devices that physically treat irrigation water were tested in the laboratory and the field. Results of these experiments indicate these water conditioners were ineffective in increasing the infiltration rate of water into the soil or in preventing calcium carbonate precipitates from clogging drip emitters under the conditions in which they were tested.
Cover crops lower soil surface strength, may improve soil permeability
by Olatunji A. Folorunso, Dennis E. Rolston, P Terry Prichard, Dianne T. Louie
| Full text HTML  | PDF  
Three and five-year studies at two Central Valley sites show that cover crops effects on soil permeability problems vary, depending on the problems cause.
Poor water penetration constitutes a major production constraint for more than 400, 000 acres of agricultural land in California. The associated economic losses are particularly appreciable in the production of fruit and nut crops. In response to a hypothesis that cover crops may improve water infiltration in orchards, studies were conducted at Davis and Ceres. After 3 years' study, results indicate major benefits are possible with the planting of cover crops.
Shorter sprinkler irrigations reduce Botryosphaeria blight of pistachio
by Themis J. Michailides, David P. Morgan, Joseph A. Grant, William H. Olson
| Full text HTML  | PDF  
Both temperature and duration of wetness directly affect infection of pistachio by the fungus.
Botryosphaeria panicle and shoot blight of pistachio caused by the fungus Botryosphaeria dothidea is favored by high temperatures, 80° to 85° F, and wetness periods longer than 12 hours. Based on these requirements, the disease becomes severe in late spring and summer when temperatures increase and after sprinkler irrigations begin. The disease was substantially reduced by shortening sprinkler irrigations from 24 to 12 hours and from 48 to 24 hours in two commercial pistachio orchards in the Sacramento and San Joaquin valleys, respectively.

Editorial, News, Letters and Science Briefs

Lessons from 1991 for a new era of water management
by Henry Vaux, Harold Carter
Full text HTML  | PDF  

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