The URL can be used to link to this page

Browse Search

Home My WebLink About20071553.tiff soil survey of Weld County, Colorado Northern Part United States Department of Agriculture Soil Conservation Service and Forest Service in cooperation with Colorado Agricultural Experiment Station A-. 2007-1553 Weld County, Colorado, Northern Part 9—Avar fine sandy loam. This deep, well drained soil 24—Eckley sandy clay loam, 0 to 6 percent slopes. is on flood plains, in swales, and on terraces adjacent to This deep, well drained soil is on smooth to moderately ^ flood plains. It formed in calcareous loamy alluvium. dissected plains and on shoulders of upland ridges. It Slope is 0 to 3 percent. formed in gravelly alluvium. Typically, the surface layer is light brownish gray fine Typically, the surface layer is dark grayish brown sandy loam 3 inches thick. The upper 5 inches of the sandy clay loam 9 inches thick. The subsoil is sandy clay subsoil is clay loam, and the lower 3 inches is sandy clay loam and gravelly sandy clay loam 6 inches thick. The loam. The upper 12 inches of the substratum is sandy substratum to a depth of 60 inches or more is gravelly loam, and the lower part to a depth of 60 inches or more sand. In some areas the surface layer is sandy loam. is sandy clay loam. In some areas the surface layer is very fine sandy loam, sandy loam, or loamy sand. Included in this unit are small areas of Altvan fine Included in this unit are soils that are similar to this sandy loam, Ascalon fine sandy loam, and Bresser Avar soil but have a dark-colored surface layer as much as 10 inches thick, have a clay loam or clay subsoil 10 sandy loam. inches thick or more, or have a light-colored surface Permeability of this Eckley soil is moderate. Available layer. Also included are numerous barren areas and slick water capacity is moderate. Effective rooting depth is 60 spots, small areas of Ascalon and Nunn soils on inches or more. Runoff is medium, and the hazard of terraces, and small areas of Bankard and Haverson soils water erosion is slight to moderate. The hazard of soil on flood plains. Included areas make up about 35 blowing is slight. percent of the total acreage. This unit is used as nonirrigated cropland and Permeability of this Avar soil is very slow in the upper rangeland. Winter wheat is the main crop. part and moderate in the lower part. Available water This unit is suited to winter wheat, barley, oats, and capacity is moderate. Effective rooting depth is 60 sorghum. Because precipitation is not sufficient for inches or more. Runoff is medium, and the hazard of annual cropping, a cropping system that includes small water erosion is slight. The hazard of soil blowing is grain and summer fallow is most suitable. Precipitation moderate. The subsoil and substratum are strongly usually is too low for crops on this unit to make efficient alkaline and saline. use of fertilizer. This unit is used as rangeland. Maintaining crop residue on or near the surface The potential plant community on this unit is mainly reduces soil blowing and helps to maintain soil tilth and alkali sacaton, blue grama, inland saltgrass, and western organic matter content. Stubble-mulch farming, wheatgrass. The average annual production of air-dry striperopping, and minimum tillage help to control erosion vegetation ranges from 500 to 1,500 pounds. and conserve moisture. Terraces reduce runoff and the If the range is overgrazed, the proportion of preferred risk of erosion and help to conserve moisture. forage plants decreases and the proportion of less The potential plant community on this unit is mainly preferred forage plants increases. Therefore, livestock blue grama, sideoats grama, and little bluestem. The grazing should be managed so that the desired balance average annual production of air-dry vegetation ranges of preferred species is maintained in the plant from 700 to 1,400 pounds. community. If the range is overgrazed, the proportion of preferred Range seeding is suitable if the range is in poor forage plants decreases and the proportion of less condition. The plants selected for seeding should meet preferred forage plants increases. Therefore, livestock the seasonal requirements of livestock or wildlife, or grazing should be managed so that the desired balance both. Salt-tolerant grasses can be grown. Other of preferred species is maintained in the plant management practices that are suitable for use on this community. unit are proper range use, deferred grazing, and rotation Range seeding is suitable if the range is in poor grazing. Livestock grazing should be managed to protect condition. The plants selected for seeding should meet the unit from erosion. Loss of the surface layer results in the seasonal requirements of livestock or wildlife, or a severe decrease in productivity and in the potential of both. Other management practices that are suitable for the unit to produce plants suitable for grazing. use on this unit are proper range use, deferred grazing, This unit is poorly suited to windbreaks and and rotation grazing. If the plant cover is disturbed, environmental plantings. The main limitations are protection from erosion is needed. Loss of the surface restricted root growth and decreased available water layer results in a severe decrease in productivity and in capacity because of the strong alkalinity and salinity of the potential of the soil to produce plants suitable for the subsoil and substratum. grazing. This map unit is in capability subclass Vis, This unit is suited to windbreaks and environmental nonirrigated, and in Salt Flat range site. plantings. Supplemental irrigation may be needed when planting and during dry periods. This map unit is in capability subclass IVe, nonirrigated, and in Sandy Plains range site. '— 36—Manzanola clay loam, 0 to 3 percent slopes. 44—Olney fine sandy loam, 0 to 6 percent slopes. This deep, well drained soil is on plains, in swales, and This deep, well drained soil is on smooth to moderately on adjacent stream terraces. It formed in calcareous dissected plains. It formed in calcareous loamy alluvium. clayey alluvium. Slopes are plane or concave. Typically, the surface layer is brown fine sandy loam 6 Typically, the surface layer is grayish brown heavy clay inches thick. The upper 12 inches of the subsoil is sandy loam 3 inches thick. The subsoil is calcareous clay 22 clay loam or loam, and the lower 10 inches is calcareous inches thick. The substratum to a depth of 60 inches or sandy loam. The substratum to a depth of 60 inches or more is calcareous clay and clay loam. more is calcareous sandy loam. Included in this unit are small areas of Aver fine sandy Included in this unit are small areas of Olney loamy loam and soils that have a sodium content of more than sand, Ascalon fine sandy loam, and Stoneham fine 15 percent. Included areas make up about 15 percent of sandy loam. the total acreage. Permeability of this Olney soil is moderate. Available Permeability of this Manzanola soil is slow. Available water capacity is high. Effective rooting depth is 60 water capacity is high. Effective rooting depth is 60 inches or more. Runoff is slow to medium, and the inches or more. Runoff is medium to slow, and the hazard of water erosion is slight to moderate. The hazard of water erosion is slight. The hazard of soil hazard of soil blowing is slight. blowing is moderate. Most areas of this unit are used as nonirrigated Most areas of this unit are used as rangeland. A few cropland. Winter wheat is the main crop. A few areas are areas are used as nonirrigated cropland. Winter wheat is used as rangeland. the main crop. This unit is suited to winter wheat, barley, oats, and The potential plant community on this unit is mainly sorghum. Because precipitation is not sufficient for blue grama, western wheatgrass, and fourwing saltbush. annual cropping, a cropping system that includes small The average annual production of air-dry vegetation grain and summer fallow is most suitable. Precipitation ranges from 500 to 1,200 pounds. usually is too low for crops on this unit to make efficient If the range is overgrazed, the proportion of preferred use of fertilizer. forage plants decreases and the proportion of less Maintaining crop residue on or near the surface preferred forage plants increases. Therefore, livestock reduces runoff, reduces soil blowing, and helps to grazing should be managed so that the desired balance maintain soil tilth and organic matter content. Stubble- of preferred species is maintained in the plant mulch farming, striperopping, and minimum tillage help to community. control erosion and conserve moisture. Terraces reduce Range seeding is suitable if the range is in poor runoff and the risk of erosion and help to conserve condition. The plants selected for seeding should meet moisture. the seasonal requirements of livestock or wildlife, or The potential plant community on this unit is mainly both. Other management practices that are suitable for blue grama, western wheatgrass, sedges, and use on this unit are proper range use, deferred grazing, buffalograss. The average annual production of air-dry and rotation grazing. Livestock grazing should be vegetation ranges from 500 to 1,500 pounds. managed to protect the soil in this unit from erosion. If the range is overgrazed, the proportion of preferred This unit is suited to winter wheat, barley, oats, and forage plants decreases and the proportion of less sorghum. Because precipitation is not sufficient for preferred forage plants increases. Therefore, livestock annual cropping, a cropping system that includes small grazing should be managed so that the desired balance grain and summer fallow is most suitable. Precipitation of preferred species is maintained in the plant usually is too low for crops on this unit to make efficient community. use of fertilizer. Range seeding is suitable if the range is in poor Maintaining crop residue on or near the surface condition. The plants selected for seeding should meet reduces soil blowing and helps to maintain soil tilth and the seasonal requirements of livestock or wildlife, or organic matter content. Stubble-mulch farming, both. Other management practices that are suitable for striperopping, and minimum tillage help to control erosion use on this unit are proper range use, deferred grazing, and conserve moisture. Terraces reduce runoff and the and rotation grazing. If the plant cover is disturbed, risk of erosion and help to conserve moisture. protection from erosion is needed. Loss of the surface This unit is well suited to windbreaks and layer results in a severe decrease in productivity and in environmental plantings. It has few limitations. the potential of the soil to produce plants suitable for Supplemental irrigation may be needed when planting grazing. and during dry periods. Summer fallow, cultivation for This unit is well suited to windbreaks and weed control, and selection of adapted plants are environmental plantings. It is limited mainly by the hazard needed to insure establishment and survival of of soil blowing where the surface layer is barren of seedlings. vegetation. Soil blowing can be reduced by cultivating This map unit is in capability subclass IVe, • only in the tree rows and by leaving a strip of vegetation nonirrigated, and in Clayey Plains range site. between the rows. Supplemental irrigation may be needed when planting and during dry periods. Summer fallow, cultivation for weed control, and selection of adapted plants are needed to insure establishment and survival of seedlings. This map unit is in capability subclass IVe, nonirrigated, and in Loamy Plains range site. —Olney fine sandy loam, 6 to 9 percent slopes. 55—Renohill fine sandy loam, 0 to 6 percent 1. - deep, well drained soil is on moderately dissected slopes. This moderately deep, well drained soil is on to highly dissected plains. It formed in calcareous loamy slightly dissected to moderately dissected plains. It alluvium. formed in calcareous loamy or clayey residuum derived Typically, the surface layer is brown fine sandy loam 6 dominantly from shale. inches thick. The upper 12 inches of the subsoil is sandy Typically, the surface layer is brown fine sandy loam 5 clay loam or loam, and the lower 10 inches is calcareous inches thick. The subsoil is clay loam 13 inches thick. sandy loam. The substratum to a depth of 60 inches or The substratum is calcareous clay loam 14 inches thick. more is calcareous sandy loam. Shale is at a depth of 32 inches. Depth to shale ranges from 20 to 40 inches. In some areas the surface layer is Included in this unit are small areas of Olney loamy loam or clay loam. sand, Ascalon fine sandy loam, Stoneham fine sandy Included in this unit are small areas of Midway clay loam, and Vona sandy loam. loam, Shingle loam, and Rock outcrop of shale. Permeability of this Olney soil is moderate. Available Permeability of this Renohill soil is slow. Available water capacity is high. Effective rooting depth is 60 water capacity is moderate. Effective rooting depth is 20 inches or more. Runoff is medium, and the hazard of to 40 inches. Runoff is medium, and the hazard of water water erosion is moderate to high. The hazard of soil erosion is slight to moderate. The hazard of soil blowing blowing is moderate. is moderate. This unit is used as rangeland. This unit is used as rangeland and nonirrigated The potential plant community on this unit is mainly cropland. blue grama, western wheatgrass, sedges, and The potential plant community on this unit is mainly buffalograss. The average annual production of air-dry blue grama, western wheatgrass, sedges, and vegetation ranges from 400 to 1,300 pounds. buffalograss. The average annual production of air-dry If the range is overgrazed, the proportion of preferred vegetation ranges from 500 to 1,500 pounds. forage plants decreases and the proportion of less If the range is overgrazed, the proportion of preferred preferred forage plants increases. Therefore, livestock forage plants decreases and the proportion of less grazing should be managed so that the desired balance preferred forage plants increases. Therefore, livestock of preferred species is maintained in the plant grazing should be managed so that the desired balance r—imunity. of preferred species is maintained in the plant ange seeding is suitable if the range is in poor community. condition. The plants selected for seeding should meet Range seeding is suitable if the range is in poor the seasonal requirements of livestock or wildlife, or condition. The plants selected for seeding should meet both. Other management practices that are suitable for the seasonal requirements of livestock or wildlife, or use on this unit are proper range use, deferred grazing, both. Other management practices that are suitable for and rotation grazing. If the plant cover is disturbed, use on this unit are proper range use, deterred grazing, protection from erosion is needed. Loss of the surface layer results in a severe decrease in productivity and in and rotation grazing. If the plant cover is disturbed, the potential of the soil to produce plants suitable for protection from erosion is needed. Loss of the surface grazing. layer results in a severe decrease in productivity and in the potential of the soil to produce plants suitable for This unit is well suited to windbreaks and environmental plantings. It is limited mainly by the hazard grazing. of soil blowing where the surface is barren of vegetation. This unit is suited to winter wheat, barley, oats, and Soil blowing can be reduced by cultivating only in the sorghum. Because precipitation is not sufficient for annual cropping, a cropping system that includes small tree rows and by leaving a strip of vegetation between grain and summer fallow is most suitable. Precipitation the rows. Supplemental irrigation may be needed when P usually is too low for crops on this unit to make efficient planting and during dry periods. Summer fallow, cultivation for weed control, and selection of adapted use of fertilizer. Maintaining crop residue on or near the surface plants are needed to insure establishment and survival reduces runoff, reduces soil blowing, and helps to of seedlings. maintain soil tilth and organic matter content. Stubble- This map unit is in capability subclass Vle, mulch farming, striperopping, and minimum tillage help to nonirrigated, and in Loamy Plains range site. control erosion and conserve moisture. Terraces reduce runoff and the risk of erosion and help to conserve moisture. This unit is well suited to windbreaks and environmental plantings. Supplemental irrigation may be needed when planting and during dry periods. This map unit is in capability subclass lye, nonirrigated, and in Loamy Plains range site. 57—Renohill-Shingle complex, 3 to 9 percent slopes. This map unit is on moderately dissected to highly dissected plains, upland ridges, and breaks. This unit is 50 percent Renohill fine sandy loam and 35 percent Shingle clay loam. The Renohill soil is in the 56—Renohill fine sandy loam, 6 to 9 percent less sloping, slightly concave areas, and the Shingle soil slopes. This moderately deep, well drained soil is on is in the steeper, convex areas. moderately dissected to highly dissected plains. It Included in this unit are small areas of Midway and formed in calcareous loamy or clayey residuum derived Tassel soils. Also included are some areas of Rock outcrop. Included areas make up 15 percent of the total dominantly from shale. Typically, the surface layer is brown fine sandy loam 4 acreage. inches thick. The subsoil is clay loam 13 inches thick. The Renohill soil is moderately deep and well drained. The substratum is calcareous clay loam 12 inches thick. It formed in calcareous loamy or clayey residuum derived Shale is at a depth of 29 inches. Depth to shale ranges dominantly from shale. Typically, the surface layer is from brown fine sandy loam 4 inches thick. The subsoil is clay 20 to 40 inches. In some areas the surface layer is loam. loam 13 inches thick. The substratum is calcareous clay loam 12 inches thick. Shale is at a depth of 29 inches. Included in this unit are small areas of Midway clay loam, Shingle loam, and Rock outcrop of shale. Depth to shale ranges from 20 to 4 inches. o Permeability of this Renohill soil is slow. Available Permeability moderate.f the Renohill v soil is i slow.dAepth is able water 0 water capacity is moderate. Effective rooting depth is 20 capacity is offis medium, m, and ere hazardg of fh water er 40 to 40 inches. Runoff is medium, and the hazard of water isis mod. Rue. T is hazard and the Oerto to erosion is moderate. The hazard of soil blowing is high. high.moderate. The hazard of soil blowing is moderate to This unit is used as rangeland. The potential plant community on this unit is mainly The Shinglessoil is shallow and well drained. It formed blue grama, western wheatgrass, sedges, and in dominantlycalcartly from loamy mshale. e.or Typically,claycy residuumsurface derived buffalograss. The average annual production of air-dry lwish brown cl a loam theik layer is vegetation ranges from 400 to 1,300 pounds. yellowish clay 4 inches thick. The underlying If the range is overgrazed, the proportion of preferred of11 material is scl. Depth loam 7 inches e from is toat a depth forage plants decreases and the proportion of less in h inches. shale throughout. h out 10 to 20 preferred forage plants increases. Therefore, livestock inches. The soil is calcareous e h grazing should be managed so that the desired balance Permeability iso the fti soil is rooting moderate.pth Available 0 `-,referred species is maintained in the plant water capacity is mediumlow Effective rai , d depth is 10 fo 20 .amenity. inches. Runoff is to rapid, and the hazard of water erosion is moderate. The hazard of soil blowing is Range seeding is suitable if the range is in poor condition. The plants selected for seeding should meet slight. the seasonal requirements of livestock or wildlife, or This ott is used l as rangeland. both. Other management practices that are suitable for l potential plant community tong the Renohill soil is use on this unit are proper range use, deferred grazing, mainly blue grama, western wheatgrass, sedges, and buffalograss. The average annual production of air-dry and rotation grazing. If the plant cover is disturbed, vegetation ranges from 400 to 1,400 pounds. The protection from erosion is needed. Loss of the surface potential plant community on the Shingle soil is mainly layer results in a severe decrease in productivity and in western wheatgrass, blue grama, alkali sacaton, and the potential of the soil to produce plants suitable for sideoats grama. The average annual production of air- grazing. dry vegetation ranges from 300 to 900 pounds. This unit is well suited to windbreaks and If the range is overgrazed, the proportion of preferred environmental plantings. Supplemental irrigation may be forage plants decreases and the proportion of less needed when planting and during dry periods. preferred forage plants increases. Therefore, livestock This map unit is in capability subclass Vle, grazing should be managed so that the desired balance nonirrigated, and in Loamy Plains range site. of preferred species is maintained in the plant community. Range seeding is suitable if the range is in poor condition. The plants selected for seeding should meet the seasonal requirements of livestock or wildlife, or both. Other management practices that are suitable for use on this unit are proper range use, deferred grazing, and rotation grazing. If the plant cover is disturbed, protection from erosion is needed. Loss of the surface layer results in a severe decrease in productivity and in the potential of the soils in this unit to produce plants suitable for grazing. The Renohill soil is well suited to windbreaks and environmental plantings. The Shingle soil is poorly suited to windbreaks and environmental plantings. The main limitations are shallow rooting depth and low available water capacity. This map unit is in capability subclass Vle, nonirrigated. The Renohill soil is in Loamy Plains range site, and the Shingle soil is in Shaly Plains range site. 5 s d i. ',• t ),fl ,e/, • s5 c x w 3f 6 .. k` '5. Yam`" i$ s:H, 4 a.* t 4 4atis 6) 5 66-9 ay. '`. U . S' '•'-'6- 56 "If; V.94,-- ^� 36,.. C 4:.,....dS'S v.5^4.wa 3 �5 ''‘'ii1 /0 • SI I 2 1 �6 �. pie4 s] 55' // __,_ 44 \ ' -''S Z0 /5 C 6 55t{f 56 57 // 56 . �.... : --.1 36 Y9 36 t. 5 0 /, 55 5) l °' 55 111 1.. 11 1 12 N 7 8 55 F� 5 • R It 74 57 5) 56 36 \ ` It + \ 29 // 5 ii 36 54 intemi/Hnf` b 05 5 55 I 13 18 °9 17 / ir ]t u 4 1 , ss 6 5] l 36 i, Sl t/ 36 54 i. 56 OS 36 56 50 56 �2 Fy 36 56 05 9,7 fi4$ 2x• 9 43 5) 36 // 36 ]I 9 36 44 0 A w t �9 �rntlr f de !.' 4 ^ 61 .5 S 11 55 05 44 • y, 3. wS a b,;,9 i aRh`65�.. R 1 4az=9L fi Y l 44 ]j H'F' 04 V to ,fjAt * t Ne.,Fa dSK' i •v• "�' ;T \ — 9 55 55 ) ) m an TABLE 10.--SOIL AND WATER FEATURES O c ["Flooding" and terms such as "rare" and "brief" are explained in the text. The symbol > means more than. Absence of an entry indicates that the feature is not a concern] _ 5' Flooding Bedrock Risk of corrosion C Soil name and Hydrologic Potential a map symbol group Frequency Duration Months Depth Hardness frost action Uncoated Concrete steel z In a r. .• 1, 2 B None --- --- >60 --- Moderate Low Low. 3 • Altvan d N I 3*: z Argiustolls. Rock outcrop. 4, 5 B None --- --- >60 --- Moderate High Low. ) • Ascalon 6•: Ascalon B None --- --- >60 --- Moderate High Low. Blakeland A None --- --- >60 --- Low Low Low. 7*, 8*: Ascalon B None --- --- >60 --- Moderate High Low. Bushman A - None--. --- --- >60 --- Low --- Low. Curablth A None --- --- >60 --- Low Low Low. 9 D Rare --- --- >60 --- Moderate High Moderate. Avar 10': Avar D Rare --- --- >60 --- Moderate High Moderate. Manzanola C None --- --- >60 --- Low High Moderate. 11*. Badland 12 A Frequent---- Brief Mar-Jun >60 --- Low Moderate Low. Bankard 13, 14 A None --- --- >60 --- Low Low Low. Blakeland 15, 16 B None --- --- >60 --- Moderate Moderate Low. Bresser 17, 18 A None --- >60 --- Low --- Low. Bushman See footnote at end of table. J A . J A N TABLE 10.--SOIL AND WATER FEATURES--Continued Flooding Bedrock Risk of corrosion Soil name and Hydrologic Potential map symbol group Frequency Duration Months Depth Hardness frost action Uncoated Concrete steel In 19*: Bushman A None --- --- >60 --- Low --- Low. Curabith A None --- --- >60 --- Low Low Low. Canyon D None --- --- 10-20 Soft Low High Low. 20 A None --- --- >60 --- Low Moderate Low. Cascajo 21, 22 C None --- --- 20-40 Soft Low High Low. Cushman 23 C None --- --- >60 --- Low High Low. Dacono 24, 25 B None --- --- >60 --- Low Moderate Low. Eckley 26*: Eckley B None --- , --- >60 --- Low Moderate Low. Dix A None --- --- >60 -- Low Low Low. Blakeland A None --- --- >60 --- Low Low Low. 27 D None------- --- --- 10-20 Soft Low High Low. Epping 28*: Haplaquolls. Fluvaquenta. ) 29 B Rare --- --- >60 --- Low High Low. Haverson 30 B None --- --- >60 --- Moderate Moderate Low. Keith 31*, 32*: Kim B None --- --- >60 --- Low High Low. I Mitchell B None --- --- >60 --- Low High Low. 33*: Kim B None --- --- >60 --- Low High Low. Shingle D None --- --- 10-20 Soft Low High Low. See footnote at end of table. w c -„4-„,„,:-:, 4 m af� TABLE 10.--SOIL AND WATER FEATURES--Continued 9 Flooding Bedrock Risk of corrosion m c Soil name and Hydrologic Potential _t map symbol group Frequency Duration Months Depth Hardness frost action Uncoated Concrete steel In Q m o. 34, 35 B None --- --- >60 --- Moderate High Low. P Manter Z 36 C None --- --- >60 --- Low High Moderate. Manzanola m 3 37 D None --- --- 10-20 Soft Low High----- Low. v Midway 38, 39 B None --- --- >60 --- Moderate High Low. Nucla 40, 41 C None --- --- >60 --- Moderate High Low. Nunn 42, 43r,44, 45---- B None --- --- >60 --- Low High Low. Olney 46, 47 B None --- --- >60 --- Low High Low. Otero 48': Otero B None --- --- >60 --- Low. High Low. Tassel D None- --- --- 10-20 Soft Low High Low. 49 B None --- --- >60 --- Moderate High Low. Paoli 50 B None to rare --- --- >60 --- Moderate High Low. Paoli 51 A None --- --- >60 --- Low Moderate Low. Peetz ) 52': Peetz A None --- --- >60 --- Low Moderate Low. Altvan B None --- --- >60 --- Moderate Low Low. : Peetz': A None 53e --- >60 --- Low Moderate Low. --- Rock outcrop. 54 C None --- --- >60 --- Low Moderate Low. Platner 55, 56 C None --- --- 20-40 Soft Low High----- Low. Renohill See footnote at end of table. A A W ) ) ) A a TABLE 10.--SOIL AND WATER FEATURES--Continued Flooding Bedrock Risk of corrosion Soil name and Hydrologic Potential map symbol group Frequency Duration Months Depth Hardness frost action Uncoated Concrete steel In 57': Renohill C None --- --- 20-40 Soft Low High Low. Shingle D None --- --- 10-20 Soft Low High Low. 58, 59 B None --- --- 20-40 Soft Moderate High Low. Rosebud ) 6o D None --- --- 10-20 Soft Low High Low. Shingle 61, 62 B None --- --- >6o --- Low High Low. Stoneham 63 D None --- --- 10-20 Soft Low High Low. Tassel 64, 65 B None --- --- 20-40 Soft Low High----- Low. Terry 66•, 67•: Thedalund C None --- --- 20-40 Soft Low High Low. Keota C None --- --- 20-40 Soft Low High Low. 68 D None --- --- 10-20 Soft Moderate High----- Low. Treon 69': Treon D None --- --- 10-20 Soft Moderate High Low. Rock outcrop. ' 70•: Uatic Torriorthents. Rock outcrop. 71, 72, 73, 74---- B None --- --- >60 --- Low High Low. Vona 75, 76 B None --- --- >60 --- Moderate High Low. Wages 77 C None --- --- >60 --- Moderate High Low. Weld fn * See description of the map unit for composition and behavior characteristics of the map unit. p N C 2 m 106 105 104 103 102 N11 i/ } it 7 34 ]1/i _ /f ]I_ II____I 1.2___ 6 _ 141 -T" H 1 DEN b' �. I ( 1 i i - I /I - ERUNG I I s IS ) f J ,, i AFRDH 1GIUfv I • � . S• -� I St41'^I ICU— L q�i I 4 i ti-115r;,ENOR , ANTON 12 I ]i I 5 BURIINGitlx- J� Lk�, HUG, I . _ I I I • F_ 39 ® one r i }) k R — �A ;I 1 COLORADO e l�..5' w[vl I'^ I� '1-5-SPRINGS l e I C ELF;I_. 11 r r yq �L 1 _ ___T Hnmu I I cJI 11 , V n 1. V1141�= L r'� I 'j kJ' 1\\� I t.} PUEBLO r-1-- _ --4-i ---- PMAR 1 38 `,) vl Lam . 1 I ' Sn I LUIS kAl6M'6ugG cc.I ,a^�� osA � Ci • /I SPRINGFIELD I Si I I �'. .1 JL II . .5 i,��iv.r_uy 37 A }i 21211412'114154 55 55� i1J IS NDAA ATLAS 2,Velum*M R8urt 31 Prepared NatioonalOce.m.eA Atmospheric ISOPLUNALS OF 100-YR 24-HR PRECIPITATION Natierr*other Wyk;001co of HydSog IN TENTHS OF AN INCH Angered for DS DipArtmort of Aplcutw Sop c o,w nWn servo;Englowcnl DNi.ion I i I 106 105 104 103 102 ALLES AND ASSOCIA1^, INC. JOB a,ore l k,^ O1(D/ 1428 North 2"d Street SHEET NO. �� 7 OF LaSalle, Colorado 80645 CALCULATED BY y'y I •/ DATE ` _ /2. — ° �� fGNMklflbri DATE /O O o -seAte- pic4tno4 ter ea, !' E'Vtiv SL,/ 7t sc . /7, r7,t< A C1 LS! 6n Ait- /tea60 Co, 2-442# art" filop i•'nD �r IZ/CJc' c_i cARAL. — C,tt rz - / Pa .Y .. ,re.c,ro,Affe)_Ll /Pc g fc',c. /re-' r/3 r7-e , dz,_6 Xt-1 is in/ Ot AisVii c57-t.,/A E. N,..G=' j G! {Fi.i,.1U.. &- rere ow /cog- /I/ "!2 K r /fiat ua t. �i -e fic-_reau on,' /liA ter• SIL, - o.prc. ..? -- ocv_'_ / (4v/tYj lY,P',L(,<iAaue D 36 / nNAa1o �J C 4 1 ji-t/+5(0/-4/8Y) /✓` 51* ( FLRr,/e/z , SJ r Ae/Jc/1 LL) C / ( ,1/4r/4 ✓F� ArL,2 �ier.1.{: X e 7 6,4A" PLC' / tr14-r/, /-/Zo_/9W /6770o / 4e r 4 C..; / 1 / A c ' 1 r /- C/°, � r /14.jj'era = S-9.9; R r L eel! 6TH e i+.',PnT"t/ ef/.4n-,, cr , 's'Ai 'WOO' ' O.I';.1.7Y h .. L7<fr...* / OOY ,. AT), 4_1 t,i✓c.�e_. Gr/; II-0 36 ' to 4. / 04 ° 30 ' pp = j V.17 t 0 .25-It? 17)C31 (X OA O/9 g E- X4 1 /0018, a f//• V?o/c at, .7= ✓1 T.. Yooyfi key. .7764,v gg f�fvf . 4 �m l/x ) - 1. 877 t-o. ,f3?[( 0j) 34 _ r,. ,, 48 _ / 4 64 milk, cv PROBLf 10L1 W In<.,Gmlm.xm 0101. ALLES AND ASSOCIATE°, INC. JOB Ca'v>-"i v�^f F&w1 r 06 of 428 North 2Dd Street SHEET NO. Z OF LaSalle, Colorado 80645 CALCULATED BY 4'. P DATE 0 /'- OCn •� CHECKED BY DATE -SCWEE- ,U/2✓+/IV 46 /ca 78 /lcc s f /4; 7r ' ✓✓� " r,t t AT-, r"7 e CU 1,• _0 hi (1'/- C �L _ ,-?LT ( 61L¢) go _ 7`1-6fry iv/ant- 00-y3 Si/(3'‘i NAT = c)? ,lcdeer t._L�Cva$ttAeo47 - /p `Too �I= 7/ - � it"ado- 5cn y 0 , O. CL, U,�• /0 ,co 0 �!- D js (/,7 - 0-2191) to Soo - g n( = 76q r— ( 9 l 0. 7 05 C/ A d f-t /t_ 11 ./r7,41, Gt` /.47, %74 - 7 /O Tj r;1 /i/,.1t,�� 74 �c r 77OO f i o - +(;) f . IC) 7171/4 ,rt.,.; `. : Go//iiz O$ './5 °['e /n 8'C' /el lc; 7 ') . t (o. t -- /7.1. 7,?; r t 0,77¢i t a, ' f af2 : , 37-r2,/y"_ tc,.4b\ -1-E �(E O. RCR7,I — �r79i t 67, 771 ( -1�, ± a.f4, —a« 7 - ° . 'foc5 C — 6, 007-, 0. 0 /37 # <,� . / 141 + o,^ t1 C(40 = G . 54 /4 I _ l7 ?f/ r „r-c, C / . ; /1(, ,4 v IAA 7-,„..44, 9 // my- , : MOD 2041 PAWN/I2.Grote NR 01471. f/ ALLES AND ASSOCIATES,INC. DDB Co,v 7-, 5- 6 0 ( o 428 North 2Bd Street SHEET NO. 4 OF LaSalle, Colorado 80645 CALCULATED BY . P DATE /C)— /2) 6 CHECKED BY DATE RtE-. sr-,4/NAGS C,t.L e• - 0,4 S,rc ARG'A 410 ant or & A/A/A t,? i) -1.<,E !'r'' C7& n 72 d4 2-7.7 4c,a / A ;-- S oo '/ opc *57 ?3=1?70 t 0- 007z Z Socc C5 2.% A' = D 175 (/../ -, C5) V a 0.395- (/m/=- 0.16 \I 2500 c Sacs, ,v„,rec 3 p-bo` ._ /It f' t L t /o = 2- 50 .t ID _ AX A. Z 3. vi s� rgo IZO C/00 - 2 '° 'std Cv 5 r G, S/e L A o. 5/ - !. q- S6a - 2-7, 7 — Z4b T Z3.9 ,t, ,,us'r c i6r/v = Lie) �, Z ? 7ro,..udrvr _ 6o;uc . 30 /20 A7 No KTN / s.Fill, `T - aa L Cx . , st,ca-t S8u774, d/f L eA//vat 6G' cyvi►46 /s = 2- x.7 (cSEsl 7' As, (ww /D% 4vfoAf) 9ooxtoo0 26.7* 2.O.77 = +7 „etc z -4f56o 0, 375C/ /- 375C/./- o./G) fizoo' - L = 32oor \3/O,o(2-5 S = -lace - 176Th 0,0 /ZS .7Loo -71 ? d. 4 -van- .f3 (7 - e 6. 5/ • 1. 4868 47. E 3S. / r pa,vp = �-� /c%, ' 36.7 „L- Go 7e.-- 7 7j-4-73 MOW 2041 hV Zg In..Wan Mm 01471. ALLES AND ASSOCIATL , INC. JOB L-nrurzeft O G d / 428 North 2nd Street SHEET NO. 1 OF LaSalle, Colorado 80645 G', P DATE /O r CALCULATED BY CHECKED/BAY DATE \// _ -3OAtE V /taco be/t/(/- P/0-41.v..a(e- t,0<'!YY IN CLt/iGG�- ka �/ = C s % C = / ,� eG,b TaLa , o 2 O-A572co &Arc, 4/,rr 1770 /Ar r 1760 oy - /o' rice c-R:_ +0 S 6 = L 101-t.3wVr.t f c_ / o _ nn 2.5 li'r'a: - /S• Lo,00tc)7 v O. 75 -r/Sc'�'._. AuC ,a L!etnciry ,'LS CA tare //,ee/f. ©uT like /.eon r /A}-L .4,e4A s. A ikvct _ Q o 4 ?. Zroe Z Svc_- 22er 2E co /goo floc, Q non / SO4 gon _ 17o8 /z- /° coo / 41e _ p 7e V 33 C/o Coo Lff/_ S /f ems 4S7b -9 5= O- o,-99 %r. 4-; ,rho /0 40 "-Hy/Net/PC- L = 69' iL or r X795- +77o c "/S/ ed22f Fr. Stapc - 6 9 °o 49'o c, 4/ SoarK G = /o i256 U/ _ /7 2a Ghr, 1-30o . 700, 9-606 460 42,ao 3 Coa 700 QoC *2070 Z ov( /Z ft /S _ Cr°, ooi(z�I OQ_ _ -79.- C rpG5 C5() /In Ca A/hi s t:L. St aPer: +83 o-172o _ O. D o . Vp r ( / F 900 fl ! N -rte; 7- _ O /6 _ _007 ! 02 /Nb i 4"f 7LT"e V_c_ - /9 '4 .0 0_ 7036 fr/--c- / 670D /°r -/ - . 76 3. V 6,701/ / r'" (.O I; 4? ' r 7lIhY l�.- `40 /6 = /O, , r �i8 y`/c 6 �J �1r ,/J7?/R�wrrr -"=<Dt-z FRO[UCI (Ne331Im.,Go,.Mm 01471. JOB Co''T,�ve-R . cCo( ALLES AND ASSOCIATES, INC. S of 428 North 2Bd Street SHEET NO. LaSalle, Colorado 80645 CALCULATED BY C P DATE /0 - to —e 6 CHECKED BY DATE 4CM,E DA,/N4i.r /p\r C.4cc. s Tc 7z ' Cy,/ '7rR rc) 4;1,3? C/./ —oiM vL o.39C//,/_ o o,,G)J -8°ort C/ 14 T/:c. - 2._./ 7 In i n-dw c s fArK / 4 < f/9 -- #o, 9.4v l ILa 7o Ini,Vvr(d 'gip. 'rg ? c.r /30 / 3G /N - c r A (6, 67) 1.4-e�9� 1-//, $) = 3/z �5 C cc 00 /N = C _ s-75) 4-5-/ //n/ �� S (t 0 cow o A:i t-1 es 7-7( 77-4,-t.. 4t& 4 4)/5 fr Aftc FICS.r. r> 2-/y /Tn Foy&rs 5d ? _ errs _ -'" A ("7 LOA -dA -3 V 775- /r ho / /Ova( Luz = i/11G/1 /`o R- /`/c t s� ou,4 : R_ w /0 u .-0.c 7 Ca.'"re-le O _- POWErROMI Inc.Grtbn,Ma 01471. CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Project Title: -- - Catchment ID: I. Catchment Hydrologic Data Catchment ID= a Area= 509.00:Acres Percent Imperviousness= jS.00;96-- .4.-ii- NRCS Soil Type= C A,B,C,or D II. Rainfall Information I(inch/hr)=C1'P1/(C2+Td)"C3 Design Storm Return Period,Tr=-P 1__,J 100 years (input return period for design storm) C1 = 0.54 (input the value of C1) C2= - (input the value of C2) — _ 03- (iiiutthe'vahietf — P1= 1.48 inches (input one-hr precipitation--see Sheet"Design Info") M. Analysis of Flow Time(Time of Concentration)for a Catchment Runoff Coefficient,C= Overide Runoff Coefficient,C= 0.24 (enter an overide C value if desired,or leave blank to accept calculated C.) 5-yr.Runoff Coefficient,C-5= Overide 5-yr. Runoff Coefficient,C= 0.24(enter an overide C-5 value if desired,or leave blank to accept calculated C-5.) Illustration •------- uverlanrl JSGEND Reach 1 flow Reack2• O Beginning Flow Direction � f Renck 3 Cat}unent Bowdon NRCS Land Heavy Tillage/ Short Nearly Grassed Paved Areas 8 Type Meadow Field Pasture/ Bare Swales/ Shallow Paved Swales Lawns Ground Waterways (Sheet Flow) Conveyance 2.5 5 7 10 15 20 Calculations: Reach Slope Length 5-yr NRCS Flow Flow ID S L Runoff Convey- Velocity Time Coeff ance V Tf ft/It R C-5 fps minutes input input output input output output Overland 0.0120 7,1.00 `,0.24 0:96 12320 1 2 3 4 5 Sum 7,100 Computed Tc= 123 20 Regional Tc= `:.`.4944 IV. Peak Runoff Prediction using Computed Tc ediction using Regional Tc Rainfall Intensity at Tc I= 0.80' ch/hr Rainfall Intensity at Tc,I= 0.80 inch/hr Peak Flowrate, Op= 97. cfs Peak Flowrate,Qp= \/97.63 cfs UD-Rational v1.00.xls,Tc and Peak() 10/17/2006, 1:16 PM \ \l'\ c ) ii‘I \ , . , \ \- ----N '\N\ „„1/4, •- ,_ "LK-J__-<.)- <:-)AVi,j1 ‘ ---1\ ----N ...4., / , \\_/,‘„.\,..s.:\c„:5,,,,, ;ALy 485 -_-\- Q ,_ - r- Gea�i; l'a.1 y. -,.:_----2.-\ -- 4 \ g4 96 / —1----\ i J 7 vvI ) 11 , i y \,,,Y -....__ m I )7 o \j , : I Am, N') (± (1\ -:` \ 7 \\:-____\271\N‘k \ \ ' \ r - \ - ) II, 1 \ra j r1 I . 1, I I - 18 \ \S >S 4831 IT \ 1171 114800 4788 ' \ \ .__— .6 \ , ),'Nf\N 2 ,—.J I --- - 4, ,c,-;) -4 ----,\\ N ? \ N -__ ___ -`,.. IN, Ai s \ \ cr." '---- ____ _ - 9g. ikon Jp 23i� �-- - -÷.' 24 � , k g �� v \ Oro y)\ .� s� -------.2- i�vw = \ rte. /... O \k ________/ i -÷ s_ ,„1/ ,---_,-- \ 1 . . 41: I `)8/ N W 4789 O 4762_ -II\- I )Iii-7)\'- ---))) r\ N _ from)hr values Duration (min) 5 10 15 30 Ratio to 1-hr 0.29 0.45 0.57 0.79 (Adopted from U.S. Weather Bureau Technical Paper No. 40, 1961.) Procedures for Estimating Values for Durations Other Than 6 and 24 Hrs The isopluvial maps in this Atlas are for 6- and 24-hr dura- tions. For many hydrologic purposes, values for other durations are necessary. Such values can be estimated using the 6- and 24-hr maps and the empirical methods outlined in the following sections. The procedures detailed below for obtaining 1-, 2-, and 3-hr esti- mates were developed specifically for this Atlas. The procedures for obtaining estimates for less than 1-hr duration and for 12-hr duration were adopted from Weather Bureau Technical Paper No. 40 (U.S. Weather Bureau 1961) only after investigation demon- strated their applicability to data from the area covered by this Atlas. Procedures for estimating 1-hr (60-min) precipitation-fre- quency values. Multiple-regression screening techniques were used to develop equations for estimating 1-hr duration values. Factors considered in the screening process were restricted to those that could be determined easily from the maps of this Atlas or from generally available topographic maps. The 11 western states were separated into several geographic regions. The regions were chosen on the basis of meteorological and climatological homogeneity and are generally combinations of river basins separated by prominent divides. Four of these geo- graphic regions are partially within Colorado. For convenience and use as an overlay on the precipitation-frequency maps, these regions are outlined on figure 19. The first Colorado region is part of the region that lies to the east of the Continental Divide and the crest of the Sangre de Cri.to and Sacramento Mountains and is south of the divide separating the drainage basins of the North and South Platte Rivers. It consists of that portion of Colorado drained by the South Platte, Republican, Arkansas, and Cimarron Rivers (Region 1, fig. 19). The second region consists of the area drained by the San Juan, Upper Rio Grande, Upper Colorado, and Gunnison Rivers and by the Green River below its confluence with the Yampa River (Region 2, fig. 19). This is part of a larger region that extends from southwestern Colorado, westward to the Wasatch Mountains of Utah, and southward through Arizona and the west- ern half of New Mexico. The third region is the, mountainous portion of the area between the Continental Divide and the crest of the Cascade Range. The portion that lies within Colorado is the northwestern portion of the State that is drained by the Yampa River and the Green River above its confluence with the Yampa .— (Region 3, fig. 19). A small portion of Colorado drained by the North Platte is Region 4, figure 19. The larger region of which this is a part includes that portion of Wyoming and Montana east of the Continental Divide. Equations to provide estimates for the 1-hr duration for 2- and 100-yr return periods are shown in table 11. Also listed are the statistical parameters associated with each equation. In these equations, the variable [(XI)(XI/X2)) or [(Xa)(X3/X,)] can be regarded as the ( value times the slope Illustratior of the line connecting the 6- and 24-hr values for the appropriate Maps, Dial return period. To illustr As with any separation into regions, the boundary can only figures 20 to 3 be regarded as the sharpest portion of a zone of transition between values are sho regions. These equations have been tested for boundary disconti- from the maps nuities by computing values using equations from both sides of the figure 6 becaus boundary. Differences were found to be mostly under 15 percent. of maps as an However, it is suggested that when computing estimates along or some slight re within a few miles of a regional boundary computations be made interpolation b using equations applicable to each region and that the average of the 24-hr valu such computations be adopted. been drawn su Estimates of 1-hr precipitation-frequency values for return rather well. H; periods between 2 and 100 yrs. The 1-hr values for the 2- and value would h 100-yr return periods can be plotted on the nomogram of figure 6 substituted in to obtain values for return periods greater than 2 yrs or less than readings. 100 yrs. Draw a straight line connecting the 2- and 100-yr values The 2- ai and read the desired return-period value from the nomogram. from the equa Estimates for 2- and 3-hr (120- and 180-min) precipitation- since the poin frequency values. To obtain estimates of precipitation-frequency value is estima values for 2 or 3 hrs, plot the 1- and 6-hr values from the Atlas on 13); the estim the appropriate nomogram of figure 16. Draw a straight line con- 24-hr values fi necting the 1- and 6-hr values, and read the 2- and 3-hr values these 1-hr volt from the nomogram. This nomogram is independent of return line, one can c period. It was developed using data from the same regions used to 50 yrs. develop the 1-hr equations. The 2- at The mathematical solution from the data used to develop gram of figure figure 16 gives the following equations for estimating the 2- and values for the 3-hr values: these points of For Region 1, 2-hr=0.342 (6-hr) + 0.658 (1-hr) (3) a straight line. figure 19 3-hr=0.597 (6-hr) + 0.403 (1-hr) (4) of the connec For Region 2, 2-hr=0.341 (6-hr) + 0.659 (1-hr) (5) example is sh figure 19 3-hr=0.569 (6-hr) + 0.431 (1-hr) (6) 2-yr 2-hr (0.8 For Regions 3 2-hr=0.250(6-hr) + 0.750(1-hr) (7) on table 13. and 4, figure 19 3-hr=0.467 (6-hr) + 0.533 (1-hr) (8) Estimates for 12-hr (720-min) precipitation-frequency values. To obtain estimates for the 12-hr duration, plot values from the 6- and 24-hr maps on figure 17. Read the 12-hr estimates at the intersection of the line connecting these points with the 12-hr duration line of the nomogram. Estimates for less than 1 hr. To obtain estimates for dura- tions of less than 1 hr, apply the values in table 12 to the 1-hr value for the return period of interest. 1-hr 2-hr 3-hr 6-hr 24-hr 2-yr 0.71 0.83 0.91 1.05 1.58 5-yr 1.38 1.99 10-yr 1.59 2.27 25-yr 1.90 2.65 50-yr 2.19 2.95 100-yr 1.86 2.39 3.35 Table 13. Precipitation data for depth-frequency atlas Table 11. Equations for estimating I-hr values in Colorado with statistical parameters for each equation Mean of Standard Corr. No.of computed error of estimate at precipitation-frequency maps Region of applicability* Equation eoeff. stations stn.vaes)s (inches) 'rations. Figures 20 through 31 hes for the 2-, 5-, 10-, 25-, 50, - 0.94 75 1.01 D074 Cinch 32 through 43 are for the May South Platte,Republican, V,=0.218+0.709[(%,)(X,/Xs)] for probabilities of 0.50, 0.20, Arkansas,and Cimarron River Y,ae=1.897 +0.4391(X.)04/X4)] .84 75 2.68 .317 )pluvial maps represent the 360- Basins(1) —0.00SZ 'artial-duration series.Data were .95 86 0.72 .085 ion-day intervals for the in the p Juan, ado Rio Grande,is, yy=—0.011 +0.942[(X,XX,IX,)] .90 85 1.96 .290 empirical factors given in the Upper Colorado,and Gunnison Y,w=0.494+0.755[(X,)(%./X.)] River Basins and Green River . Basin below confluence with the interval selected was designed to Yampa River(2) scription of the isopluvial pattern Yampa and Green River Basins Y,=0.019 +0.711[(X,)Of,IX,)] .82 98 0.40 .031 isoline interval over most of the above confluence of Green and + 0.0012 pion i.. .2 in. for in.and .0 in., Yampa Rivers(3) V,, 0.338+0.670[(Xa)(Xs/X.)] .80 79 1.04 .141 4 in. en 3.0 and 5.0 in., +0.0012 99 1.040 0.60 . 42 5.0 in._.the an,in southwestern Y.=0.028+0.890[(X,1(X,/X,)] .93 ,pci the annual maps use an North Platte(4) V100=0.671 +0.757[(X,)(X./XJ] 1,71 .236 precipitation-frequency. inOthmapsf values t of-hr -0.003Z .91 88 r2.0 Onthemapsforthe sees 'nr and0precipitation-frequency0po values *Numbers in parentheses refer to geographic regions shown in figure 19.See text for more complete description. 50 0.20 probability level (on tober season). At longer return List of variables ne upper limit of the 0.1-in.isoline V2 =2-yr 1-hr estimated value ,intain the isopluvial gradient and Y1,,=100-yr 1-hr estimated value br the 6-hr duration, the isoline X, =2-yr 6-hr value from precipitation-frequency maps 15 percent,with some differences as large as 40 to 50 low 3.0 in. to 0.4 in.over 3.0-in. Xy =2-yr 24-hr value from precipitation-frequency maps percent.rc About half o the individual idua have differences sel large rChao 10 Dashed intermediate lines have X. =100-yr 6-hr value from precipitation-frequency maps percent.These differences indicate that frequency values computed eparated isolines and in regions X. =100-yr 24-hr value from precipitation-frequency maps from an annual series of rainfall amounts only would be different veep the normal thatisopluvial interval Z =point elevation in hundreds of feet from those composed of all-precipitation values, and two separate olation. "howl• that close within sets of precipitation-frequency maps were needed. hap have been hatched on the low- Snowfall observations are made at only about 15 percent of the precipitation stations used in this study. For this reason, a rainfall-frequency study could not be made by direct methods. ,recipitetloe-frequency volute. The Since most snowfall occurs during the colder half of the year, a esent frequency values of precipita- series containing only values for the May to October season was any hydrologic purposes, from recipita compared with the series that was based on rainfall only.The two seed in a different manner p that series were in good agreement, except for a slight bias toward non of snow amounts to pre tit higher values for the May to October season. This bias results ado and the Rocky Mountain States from some large amounts in late October and early May occurring Colorado, New Mexico. and Utah) as snow and thus excluded from the rainfall-only series.The aver- , there were about 50 stations per age difference is only about 4 percent, with no consistent Fo ion of snowfall uchstation,as part of the ( ence toward higher elevations or particular geographic regions. prefer- m. For each such two data € Two sets of.maps were prepared for Colorado.The first set td under Interpretation of Results. consists of annual maps based on precipitation data from all ting Frequency Values. • months of the year without regard to the type of precipitation;rain, e 2-yr 24-hr value for the series cos- u rain and snow mixed, all snow, hail, etc.The second series takes u without regard to the type of pre- ; iii • precipitation values from the months May to October.No attempt talue s.ahe series with snow occur- nwas made in this second series to differentiate between types of this 's. latitude (fig. 15) shows a�° o precipitation occurring within these months,but the investigations maxin._..s in the latitude of Colorado mentioned in the preceding paragraph indicate that these maps will•hdo, the all-precipitation series tends 'ET"3.i,.. approximate the values that would be obtained by using a data t higher than the series with snow a series made up of precipitation events that are exclusively rain. moon of the data shows that in the 31:cSince data for only part of the year were used, these maps have smoothed 6,000-ft contour the differ- »� ° ,, been labeled with the appropriate probabilities rather than with a n,�. a ..,o y. are minor. With data from this area ' ,.,,A,,._„o„,ALA t,c.,..do„°A' return period in years(figs. 32� tween the two series averages about ,.,,AL,.-„o°. ,„FALL ONLY Hello