1. Law School for Journalists Colorado Bar Association Ken Knox Division of Water Resources March 13, 2007

2. COLORADO HISTORIC AVERAGE ANNUAL STREAM FLOWS (acre feet) OFFICE OF THE STATE ENGINEER COLORADO DIVISION OF WATER RESOURCES Prepared by the Hydrographic Branch (2003 Revision) Historic averages obtained from USGS Water-Data Report CO-02 YAMPA WHITE LITTLE SNAKE ELK NO. PLATTE CACHE LA POUDRE SOUTH PLATTE NORTH FORK REPUBLICAN SOUTH FORK REPUBLICAN NO. FORK ARKANSAS NO. FORK UNCOMPAHGRE McELMO MANCOS LA PLATA ANIMAS & FLORIDA LOS PINOS PIEDRA SAN JUAN CONEJOS PURGATOIRE GUNNISON SAN MIGUEL LARAMIE COLORADO DOLORES RIO GRANDE 1,531,000 555,200 4,500,000 414,300 1,127,000 404,600 311,100 111,800 37,100 36,890 25,580 670,100 173,700 446,900 + 291,200 235,800 322,100 653,300 394,300 153,000 593,600 172,000 219,800 943,000 330,500 547,300 291,20 0 268,600 1,872,000 125,100 31,890 313,200 96,300 49,640 47,020 164,200 89,820 699,200 528,200 879,800 413,200 329,200 45,590 476,300 229,200 185,200 403,400 31,680 28,750 69,750 FOUNTAIN APISHAPA 18,970 HUERFANO 26,930 GRAPE 24,933 BEAR 33,760 58,146 88,051 63,038 126,800 270,500 204,400 404,400 875,600 265,800 99,500 634,500 ST. VRAIN BOULDER 158,800 50,050 PICEANCE 27,700 152,600 6 5 2 1 3 4 7 505,600 279,70 0 2,799,000 334,400 54,760 85,540 EAST TOWARD ATLANTIC OCEAN 1,373,000 af WEST TOWARD PACIFIC OCEAN 8,867,450 af TOTAL LEAVING COLORADO 10,240,500 af ROARING FORK EAGLE BLUE TOMICHI SOUTH FORK SAN JUAN - CHAMA 94,180 At Benkelman, NE

3. 1,530,000 560,000 310,000 4,500,000 510,000 1,780,000 320,000 110,000 400,000 164,000 YAMPA WHITE COLORADO GUNNISON DOLORES SAN JUAN ARKANSAS SOUTH PLATTE N. PLATTE LARAMIE RIO GRANDE WEST SLOPE Population: 467,000 Irrigated Acres: 880,000 EAST SLOPE Population: 3,869,000 Irrigated Acres: 2,270,000 2000 Population Irrigated Acres and Flows

4. Water Management and Allocation Water Rights –Surface water rights from rivers and streams –Reservoir storage rights –Ground water rights Interstate River Compacts

5. Colorado’s Water Right System Colorado uses the Prior Appropriation Doctrine which means those that first put water to use are entitled to get their water first during periods of water shortage. In Colorado water is a separate property right - that is it can be sold separately from the land. This is in contrast to the Riparian Doctrine that exists in the eastern part of the United States which recognizes water rights as being attached to the land.

6. Water Administration Water Allocation –173,000 Water Rights –105,000 Structures –400,000 observations –30,000 water diversions and storage records –1500 court consultations –50 court litigation –420 subdivision review –217 Substitute Water Supply Plans

8. In 1879, Colorado established Water Commissioners to distribute water rights in priority based upon principle of “First In Time... First In Right”

9. Reservoir Storage Current Storage (acre-feet) Restricted Storage* Total acre-feet (# Dams) Division 11,787,81033,900 (99) Division 2893,54489,200 (31) Division 3297,2619,700 (3) Division 41,447,9484,200 (28) Division 51,166,0402,990 (19) Division 6165,3871,400 (11) Division 7665,3561,460 (7) Total6,423,345142,850 (198) * August 20, 2002 1990 – 2001: 49 new dams with a combined storage of 120,000 acre- feet Division 2: Two Buttes 31,500 AF and Cucharas 33,000 AF; very expensive reconstruction necessary

10. Major Aquifer Systems

11. GROUND WATER USE AQUIFERAVERAGE ANNUAL SUPPLY (Acre-Feet) Denver Basin80,000 South Platte Alluvium600,000 Arkansas River Alluvium150,000 San Luis Valley Aquifers800,000 High Plains – Ogallala1,000,000 Bedrock Aquifers – Mountains70,000 TOTAL2,700,000

12. 18 States Rely on Colorado Water

13. Interstate Compacts Colorado River Compact - 1922 La Plata River Compact - 1922 South Platte River Compact - 1923 Rio Grande River Compact - 1938 Republican River Compact - 1942 Costilla Creek Compact - 1944 (Rev. 1963) Upper Colorado River Compact - 1948 Arkansas River Compact - 1948 Animas-La Plata Project Compact - 1969 U.S. Supreme Court Cases Nebraska v. Wyoming - 325 U.S. 589 (1945) Wyoming v. Colorado - 353 U.S. 953 (1957)

14. I NTERNATIONAL A ND I NTERSTATE D OCUMENTS A FFECTING C OLORADO’S U SE O F W ATER International Treaties Mexican Treaty on Rio Grande, Tijuana, and Colorado’s Rivers – 1945 1906 Convention with Mexico on the Rio Grande above Ft. Quitman, Texas

15. S TATE O F C OLORADO I NTERSTATE C OMPACTS S TATE O F C OLORADO I NTERSTATE C OMPACTS Methods of Allocating Water Among States 1Allocation of a portion of the long-term undepleted basin water supply to each state on the basis of consumptive use (man-made depletions) aColorado River Compact - Acre-feet per year of depletions bRepublican River Compact - Acre-feet per year of depletions 2Delivery of a portion of an indexed supply to the stateline aRio Grande Compact - Variable index and delivery obligation for calendar year bLa Plata River Compact - One-half of indexed flow to stateline the next day 3Application of Doctrine of Prior Appropriation across stateline aCostilla Creek Compact bSouth Platte River Compact

16. Thank You http://www.water.state.co.us/