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<br />"";","""..;",,.;;,.PA;rliERSGN ,:t;fOblOW,:. "";"''''i.'::ItIi,,,..i ;,,;lNitli\n'itlie'jim~l\iliC.iiI!~,,,\~,~qe'.. a,a,!I$2',0.wQocs,cof '.. , . ,. . .,,'.' .. PROBLEMS>, .:' . ., ." ".. . ,,,',,,,S'\~,<;.ated,oo,tlie'~~",~ll(<\'-"i!~,*,,
<br />U.SDA ',W A TER,QUAUTY ~YP.RQtO<i~c..-,_UNli, AeEA' " " . ~. -~Ii~~Ei~!~, J.,!,~~J~~~~~~,h:C~:~~.".r~.",~~?!;,~1 ~~~,t~"~()'~~~';_'.~~~~1 ,~~~:~~~;~~reationi"an9, irrig~~~~ ,~.~~,~~ge.
<br />lspanrc women, 's.even unlts::ol 2gov:ernment, ten onenta The 'Patters'on Holfow, Hydrologic' Unit' Area 'Obtains' wate-f -,
<br />mat~:\en hispanIc' males~~;nfn-e"c~'rpo'rate- owners _and 384 from the- Rocky Ford Highline, Oxford4' Otero, 'Roeky"F6rd, The "aqtiatic habitat in the Arkansas ,Riv_e:r, ,_i~' '~ff~~t~':~6y-;.4;:, :"
<br />white male owneiS<' ,There'are 505 operating units with and Catlin Canals. These canals divert water from the I sediment, ,salt, nutrients, and pesticides. Spawning,''8r~iS:JL:
<br />255 >OpeF8to:~:~':"'tJt~n-~.so:-<8cr-es;'""'~,Censas---.:aata" -AfkaAsas Rivet befor-e the- watef, ,quality, iR-..'the, ri.v'8f,,'has-',,:,~ -:aM~fOod$?ur.ces.can besmotb~ed,.bV_ tbe-s~1'f::IiM~ '<
<br />indicates approximately; ,SO .percent of tl:ie operators are deteriorated significantly. The quality of the water diverted becomes turbid affecting t!'1e ,f~eding ability o~ 'th~,,~.~,~f.'~::t
<br />'limited resource -farmers.-:.- '. averages :~out 500 ppm TDS in these,can~ls. fauna., Nutrients in the runoff as well as the pesticides can:<".;
<br />. _ ~ ,_ , , ," , . . _ ta~ the available oxygen.
<br />Cropping patterns ,.withi~ .the area' consists of 35% corn, The Arkansas River downstream from the project area has,
<br />24%"':JdfEdf_a;":,-:'1'6,"- ;'vegetables, < :1 '2% "-small grains, 8% a salinitY- ~nc~ir81:i.on,of._:apptoximateIY -2:_590, PP~J;.~:,~.,
<br />sorghums, and '5~'drv beans. The vegetables are primarily Salinity levels thereforo_change,rapidly in this 25 mile reactl
<br />melons. onions, tomatoes. and watermelons with smaller of th~ river. . .
<br />acreages of asparagus, parsnips. lettuce, cucumbers,
<br />peppers, potatoes, pumpkins and swe.et corn.
<br />
<br />. ".-<.c"-
<br />
<br />"'--"'''"
<br />
<br />PUEBLo -.OTERO COUNTIES. COLORADO.
<br />
<br />, :,,1
<br />
<br />. INTRODUCTION >
<br />
<br />The Lower Arkansas River in 'Colorado, according too. t~e
<br />Cooperative Extension, is the most saline stream ()f it size
<br />in the United States. The average salinity levels of canal
<br />systems east of Pueblo increase from 300 ppm Total
<br />Dissolved Solids (TOS) to over 4,000 ppm TDS near the
<br />Kansas state line. Shallow wells in the area have similar
<br />TDS'concentrations. Water containing more than ~,obo
<br />ppm TDS has often been assumed to be unsuitable for
<br />irrigation, but such waters have been used in the Arkansas
<br />Valley for many years. Approxi~atEdy two- thirds of the
<br />290..000 acres of irrigated land is being irrigated with Class
<br />C4 water, the U.S. Salinity Laboratory's ,hi:,g~~t' ~,~linity
<br />hazard classification. High sediment_and: salinity problems
<br />were identified in the Colorado Nonpoint Assessmentreport
<br />for this reach of wa~er.
<br />
<br />. ORIGIN OF SAlTS>
<br />
<br />Tt~e :',two basic processes which are responsible for high
<br />salinity levels are salt pickup and salt concentration. They
<br />ocCur both naturally and as a result of action by man. Man
<br />caused salt pickup occurs from ,irrigation of - crops and
<br />lawns, municipal use and other activities that encourage
<br />seepage and deep percolation. Salt concentration occurs
<br />when water is consumed by either evaporation or lost by
<br />transpiration though plants with the salts left behind with
<br />the remaining water.
<br />
<br />. DESCRIPTION OF AREA >
<br />
<br />The Patterson Hollow USDA Water Quality Hydrologic Unit
<br />Area is located in Pueblo and Otero Counties, Colorado.
<br />The hydrologic unit consists of abom 89.,850 acres. Of the
<br />total acreage, 3,100 acres_ are urban, 26,850 acres are
<br />ftJngeland' ','end ",.59..'700. '8Cfes" are"""irrigated ,. cropland.'
<br />Irrigation water is furnished by the Rocky Ford Highline.
<br />Oxford, Otero, Rocky Ford, and Catlin canals.
<br />
<br />The land is located south of the Arkansas River. from the
<br />eastern edge of La Junta where the Otero Canal outlets
<br />into Kings Arroyo, north of the Highline Canal and east of
<br />the HighUne/Oxford gaging station on the Arkansas River.
<br />This area contains the towns of Fowler. Manzanola. Rocky
<br />Ford, Swink and La Junta. The Colorado State University
<br />Arkansas Valley Research Center is located in the area, just
<br />east of Rocky Ford.
<br />
<br />Climatically, - the area is characterized by warm summers
<br />and mild winters. The -area has a 180 day growing season
<br />with an average annual precipitation of 11.5". Elevation_
<br />varies from about 4040-4350 feet above sea level.
<br />
<br />The - soil in '-the - project area are generally loams and silty
<br />clay loems with slopes of mainly 0-1 percent, but with
<br />some slopes up to three percent. Geographically, the valley
<br />rests in a U-shaped trough, cut into Cretaceous shale and
<br />limestone bedrock.
<br />
<br />Most of the irrigated soils are well suited to a wide range
<br />of crops including the high value cash crops. The soils vary
<br />from low to high in water intake, water holding capacity,-
<br />permeability, and water erosion which magnifies the need
<br />for proper-management.
<br />
<br />
<br />IRRIGATING
<br />EVERY
<br />/' OTHER ROW
<br />....,.'It.. CONSERVES
<br />~......,:'":: WATER AND
<br />IMPROVES
<br />QuALITY
<br />
<br />Crops grown in this area are !lot affected by salinity due to
<br />the higher quality water. Vegetables, corn and other salt
<br />sensitive crops are grown in the area with little yield
<br />reduction from water quality problems. In contrast.
<br />irrigation downstream along the Arkansas River is limited to
<br />less salt sensitive and generally lower income crops such as
<br />alfalfa. sorghum and wheat. Crop yields are reduced by the
<br />poor quality water. Water quality is also a problem for
<br />domestic, municipal, industrial, recreational and fisheryuse.
<br />
<br />The soils in the are~ are well sUited to ~lIlocally adapted.
<br />crops.- ,-The loa,mY.- soils management Jlr~bl~ms i~cl~~e:
<br />maintaining good ''tilth 'and,_g~tting, "gOod }-dist6b~~on"'-~f"
<br />irrigation .-water.: _Managemeiit of irrigation water-on s:lopes
<br />greater than,'ona percent:,i'~__Jl~eded to reduce.~rosion,'and
<br />loss of ,planCnUtrierits"" -aM pesticides. The soils 'an!
<br />calcareous thr~ughollt .~h~ir, profile with salts generally
<br />leached out of the surface l~yers. The lower profiles are
<br />more sandy. SOnle areas have limestone at a depth
<br />beginning at three and one:'half feet.
<br />
<br />Erosion on the irrigated 'Iand is also a problem. The
<br />sediment carries salts, fertilizers, pesticides, insecticides
<br />and other chemicals and deposits them into the Arkansas
<br />River. This project area with its significant vegetable crop
<br />acreage use substantial amounts of fertilizer and chemicals.
<br />Nitrate levels have increased sharply in the last 20 years in
<br />the Arkansas River, but remain below the maximum
<br />allowable for public drinking water supplies. This indicates
<br />that the farmers are not making the most efficient use of
<br />their fertilizers. Attention to this problem is needed. The
<br />problems with operation and maintenance of the irrigation
<br />systems are also increased due to the sediment _ and
<br />erosion. Furrow irrigation is used on most r9w crops.
<br />Corrugation usage predominates on the fields growing
<br />alfalfa. Low irrigation efficiencies and less than adequate
<br />water available compounds the problems of the area.
<br />
<br />. '~~.~,
<br />
<br />The _ ongoin,g USDA prog,rems are the only effort presently
<br />.'b<liWjj'<<SOcffOI'Wiitiil' <iOi\1iWiiilp,_nt in thi'....r"":'The'.'-"
<br />Lower Arkansas River Basin Water Quality Study is
<br />underway to better quantify water quality problems and
<br />needs in the basin.
<br />
<br />The lack of Best Management Practices (BMP's) being
<br />applied in the area pennits the over and under irrigation.
<br />deep percolation, and erosion to occur. This causes the
<br />salt.. . nutrient, sediment. and pesticide buildup in the
<br />Arkansas River and in downstream irrigation canals.
<br />Sediment build up is also occurring in the John Martin
<br />Reservoir just downstream from the project area. This
<br />
<br />
<br />
<br />'oj
<br />
<br />While s9m~ economic value may be lost in recreation--\
<br />dama~~~'iittle - data is available from the biological impacts. 'i
<br />This'-'is' :true" for' John Martin Reservoir where _ fishing i~
<br />popular and "also in areas above John Martin where ,water.
<br />quality degradation has resulted in very little remaining
<br />f.ishing opportunities.
<br />
<br />;';.,' , .;~
<br />
<br />.- ','" ..
<br />'" - 6sJECTIVes ..
<br />
<br />The objectives of the Patterson Hollow W~ter Quality
<br />project are'to improve the Arkansas River water, quality by
<br />reducing the amount of salts_ reaching the river in return
<br />flows and.improve,the irrigation water management being
<br />practiced-'in the area.
<br />
<br />Improved irrigation water management will control the
<br />amount of deep percolation and runoff from the irrigated
<br />cropland. Reducing the amount of water moving through
<br />the soil profile will minimize the pickup and transportation
<br />of salts, nutrients, and pesticides.
<br />
<br />Installation of planned practices will improve the irrigation
<br />efficiencies from the present of approximately 40 percent
<br />to 60 percent. A reduction of approximately four inches of
<br />deep percolation is expected with this improvement in
<br />efficiency. This reduction in deep percolation means that
<br />over .one ton per acre of salt (over 60,000 tons/year from
<br />the total area) can be eliminated from the river.
<br />
<br />Reduced salinity in the Arkansas River will broaden the
<br />potential cropping patterns and yields in the downstream
<br />irrigated ar~as,snd improve the fishery habitat in ,the river
<br />a,nd Jqb.".~rtin Reservoir.
<br />
<br />>>-<-'~'"~ ."-'--~'"
<br />
<br />Improved farm irrigation systems will allow for reduced
<br />operation and management costs to the land owner and
<br />operators in the project area. This in turn will improve the
<br />overall economic viability of the county.
<br />
<br />-0( ACl10N ..
<br />
<br />It has been generally accepted that irrigation salinity pickup
<br />is related to canal seepage and excess deep percolation of
<br />irrigation water. In irrigated areas sediment is produced
<br />from erosion caused by improper irrigation methods.
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