Technical Memorandum
To: Chandler Peter, U.S. Army Corps of Engineers
From: Seth Turner, CDM Kelly DiNatale, DiNatale Water Consultants Matt Bliss, Hydros Consulting Jordan Dimick, CDM
Date: August 1, 2011
Subject: Water Administration in the Cache la Poudre River Basin
The purpose of this memorandum is to provide the reader with an overview summary of water administration in the Cache la Poudre (Poudre) River Basin in northern Colorado. This document was prepared at the request of the U.S. Army Corps of Engineers (USACE) in conjunction with the National Environmental Policy Act (NEPA) reviews and preparation of the Environmental Impact Statements (EISs) for the proposed Northern Integrated Supply Project (NISP) and the proposed expansions of the existing Halligan Reservoir and the existing Milton Seaman Reservoir.
The Applicant for NISP is the Northern Colorado Water Conservancy District (NCWCD or District), acting on behalf of 15 participating municipal and rural domestic water providers that are located within the District's boundaries in Boulder, Larimer, Morgan, and Weld Counties in northern Colorado. The Applicant's Proposed Action is the construction of the 170,000 acre-foot (AF) Glade Reservoir, located in the Hook and Moore Glade area northwest of Fort Collins near Ted's Place, off of the main channel of the Poudre River, and the 45,624 AF Galeton Reservoir, located on the plains northeast of Greeley and east of Ault. Additional infrastructure and exchange operations would be necessary to facilitate delivery of water to the project's participants.
The City of Fort Collins and the North Poudre Irrigation Company (NPIC) are jointly pursuing the expansion of Halligan Reservoir, located on the North Fork of the Poudre River (North Fork), above Livermore. The City of Greeley is seeking to enlarge its Milton Seaman Reservoir, also located on the North Fork, about a mile upstream of its confluence with the Poudre River mainstem. These two reservoir enlargement projects are primarily for developing an increased water supply for Fort Collins and Greeley, respectively. Collectively, these two projects are known as the Halligan-Seaman Water Supply Projects (HSWSPs).
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Contents
Section 1 – Introduction ...... 1 1.1 Poudre Basin Setting ...... 1 1.2 Source Material and Overview ...... 1 Section 2 – Colorado Water Law ...... 4 2.1 The Doctrine of Prior Appropriation ...... 4 2.2 Water Rights Associated with NISP and HSWSPs ...... 6 2.3 Duties of the Water Commissioner ...... 8 2.3.1 Record Keeping ...... 8 2.3.2 Regulate Headgates ...... 9 2.3.3 Distribute Storage Water ...... 9 2.3.4 Distribute Transmountain Water ...... 9 2.3.5 Delivery of Augmentation and Exchange Water ...... 9 2.3.6 Inspections ...... 9 2.3.7 Restriction Enforcement ...... 9 2.4 Interstate Compacts and Decrees ...... 10 2.5 Recommended Further Reading ...... 10 Section 3 – Historical Streamflows ...... 11 Section 4 – Transbasin Diversions ...... 24 4.1 Transbasin Diversions into the Poudre Basin Headwaters ...... 24 4.1.1 Grand River Ditch ...... 27 4.1.2 Laramie-Poudre Tunnel ...... 27 4.1.3 Skyline Ditch ...... 27 4.1.4 Bob Creek Ditch ...... 27 4.1.5 Deadman Ditch and Wilson Supply Ditch ...... 27 4.1.6 Cameron Pass Ditch ...... 28 4.1.7 Michigan Ditch ...... 28 4.2 Colorado-Big Thompson Project ...... 28 Section 5 –Mountain Water Supply Systems ...... 32 5.1 High Mountain Reservoirs ...... 32 5.2 Halligan Reservoir and Milton Seaman Reservoir ...... 34 5.3 Joint Operations Plan ...... 35 Section 6 – Major M&I Water Providers in the Poudre Basin ...... 37 6.1 Fort Collins and Greeley Pipelines ...... 37 6.2 Tri-Districts ...... 39 6.3 Pleasant Valley Pipeline ...... 39 Section 7 – Major Irrigation Water Users in the Poudre Basin ...... 40 7.1 Average Annual Diversions for Agriculture...... 40
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7.2 The "Big Four" Canals ...... 42 7.2.1 North Poudre Canal ...... 44 7.2.2 Larimer County Canal ...... 45 7.2.3 Larimer Weld Irrigation Canal ...... 46 7.2.4 New Cache la Poudre Ditch ...... 46 7.3 South Side Ditches ...... 47 Section 8 – Water Exchanges in the Poudre Basin ...... 50 8.1 Overview of Water Exchanges in the Poudre Basin ...... 50 8.2 Major Exchanges Represented in EIS Modeling ...... 52 Section 9 – Other Key Administrative Issues ...... 54 9.1 River Dry-up Points ...... 54 9.2 Fossil Creek Reservoir Inlet Operations ...... 57 9.3 Fish Hatchery and Recreational Minimum Flows ...... 58 Section 10 – References ...... 62
Tables
Table 1. Conditional Storage and Exchange Water Rights Proposed to be Used by NISP and the HSWSPs ...... 7 Table 2. Streamflow at Key Gages on the Poudre and South Platte Rivers ...... 11 Table 3. Transbasin Diversion Structures Delivering to the Poudre River Basin ...... 24 Table 4. Monthly and Annual Transbasin Imports to Poudre Basin, WY 1950-2009 ...... 25 Table 5. Average Annual Simulated C-BT Deliveries to Poudre Basin Agricultural Users, 1950-2005 ...... 30 Table 6. Greeley and Fort Collins M&I Pipeline Diversions from the Poudre River ...... 37 Table 7. Major Poudre Basin Irrigation Diversions ...... 41 Figures
Figure 1. Water Districts Located in Water Division 1 ...... 2 Figure 2. Example of Water Rights Administration by Priority ...... 4 Figure 3. Annual Flow Volume, Cache la Poudre River at Canyon Mouth ...... 14 Figure 4. Hydrograph of Average Daily Flows, Cache la Poudre River at Canyon Mouth ...... 15 Figure 5. Annual Flow Volume, Cache la Poudre River at Lincoln Street ...... 16 Figure 6. Hydrograph of Average Daily Flows, Cache la Poudre River at Lincoln Street ...... 17 Figure 7. Annual Flow Volume, Cache la Poudre River above Boxelder Creek ...... 18
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Figure 8. Hydrograph of Average Daily Flows, Cache la Poudre River above Boxelder Creek ...... 19 Figure 9. Annual Flow Volume, Cache la Poudre River at Greeley ...... 20 Figure 10. Hydrograph of Average Daily Flows, Cache la Poudre River at Greeley ...... 21 Figure 11. Annual Flow Volume, South Platte River at Kersey...... 22 Figure 12. Hydrograph of Average Daily Flows, South Platte River at Kersey ...... 23 Figure 13. Transbasin Diversions to the Poudre River Basin ...... 26 Figure 14. C-BT Releases to Poudre River via Hansen Supply Canal, WY 1952-2009 ...... 31 Figure 15. Greeley and Fort Collins1 Pipeline Diversions from the Poudre River, IY 1950-2009 ...... 38 Figure 16. Canals and Irrigated Lands Associated with the Big Four ...... 43 Figure 17. Canals and Irrigated Lands Associated with the "South Side Ditches" ...... 48 Figure 18. Poudre River Dry-up Points ...... 56 Figure 19. Poudre River Fish Hatchery and Recreational Minimum Flow Points ...... 60
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Acronyms AF acre-foot AFY acre-feet per year C-BT Colorado-Big Thompson CDM Camp Dresser & McKee Inc. CDSS Colorado Decision Support System cfs cubic feet per second CFWE Colorado Foundation for Water Education CTP Common Technical Platform CWCB Colorado Water Conservation Board DWR Division of Water Resources DWRF Drake Water Reclamation Facility EIS Environmental Impact Statement ELCO East Larimer County Water District FCLWD Fort Collins-Loveland Water District HSWSPs Halligan-Seaman Water Supply Projects ISF instream flow IY irrigation year JOP Joint Operation Plan LRE Leonard Rice Engineers M&I municipal and industrial mgd million gallons per day MOA Memorandum of Agreement NCWCD, District Northern Colorado Water Conservancy District NEPA National Environmental Policy Act NISP Northern Integrated Supply Project NPIC North Poudre Irrigation Company NWCWD North Weld County Water District PBN Poudre Basin Network
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Acronyms Poudre Cache la Poudre PVC Poudre Valley Canal PVLC Pleasant Valley and Lake Canal PVLCC Pleasant Valley & Lake Canal Company PVP Pleasant Valley Pipeline ROD Record of Decision RTi Riverside Technology, Inc. SCFP Soldier Canyon Filter Plant SPDSS South Platte Decision Support System SWSI Statewide Water Supply Initiative USACE U.S. Army Corps of Engineers USFS U.S. Forest Service USGS U.S. Geological Survey WSSC Water Supply and Storage Company WTF Water Treatment Facility WWTF Wastewater Treatment Facility WY water years
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Section 1 – Introduction 1.1 Poudre Basin Setting The Poudre River is tributary to the South Platte River, and it extends from headwaters in the Rocky Mountains along the Continental Divide in and north of Rocky Mountain National Park to its confluence with the South Platte River just east of Greeley. For water rights administration, the Poudre Basin is known as Water District 3 and is a part of the larger Water Division 1, which includes the entirety of the South Platte River Basin that lies within Colorado and encompasses 16 water districts. Most of these water districts make up the headwaters and mainstem of the South Platte River (Water Districts 1, 2, 8, 23, 64, and 80) and its major tributaries—including the Big Thompson River (Water District 4), St. Vrain Creek (Water District 5), Boulder Creek (Water District 6), Clear Creek (Water District 7), and Bear Creek (Water District 9). Water Division 1 also includes the Republican River (Water District 49) and Arikaree River (Water District 65) on the eastern plains as well as the Laramie River (Water District 48) and Sand Creek (Water District 76), located in north-central Colorado and tributary to the North Platte River in Wyoming. Figure 1 depicts the water districts of Water Division 1, with the Poudre Basin highlighted.
The daily administration of water in each Water District is overseen by the Colorado Division of Water Resources (DWR) through the Water District 3 Water Commissioner and his or her deputies. George Varra is the Water Commissioner for Water District 3; he began as deputy Water Commissioner in 1988 and became the Water Commissioner in 2000. As described by Wilkins- Wells et al. (2002), "The Water Commissioner oversees diversions for direct flows and for storage purposes, as well as overseeing the exchanges on a daily basis." The Water Commissioner determines which water rights are in priority on a daily basis and is responsible for the accounting. Additional details regarding the duties of the Water Commissioner are provided in Section 2.3.
1.2 Source Material and Overview As part of ongoing efforts for the development of the South Platte Decision Support System (SPDSS), the DWR, the Colorado Water Conservation Board (CWCB), and the consultants working with these agencies have published extensive documentation of key irrigation systems, municipal water providers, transbasin diversions, and other aspects relevant to the administration and modeling of water use throughout the South Platte Basin, including the tributary Poudre Basin. This documentation will be heavily relied upon in this memorandum, and the reader is encouraged to seek out the source documentation if more detailed information regarding a particular topic or structure is desired.
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Figure 1. Water Districts Located in Water Division 1
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Links will be provided to download these documents from the SPDSS website; the Adobe PDF reader is required to view most of the documents. If any of the links to SPDSS memoranda do not work properly, the documents can also be accessed via the main SPDSS documents website. The first such document will be referred to herein as the SPDSS Water District 3 memo (Leonard Rice Engineers [LRE] 2004a), and it provides an overview of key structures and administration in the Poudre Basin. This memo is available here: Task 3 – Identify Key Diversion Structures (Note that this link is to a zip file that includes similar memoranda for most of the Water Districts of the South Platte Basin).
Also useful in conjunction with the SPDSS Water District 3 memo is the Water District 3 straight- line diagram, available here: Water District 3. This diagram provides a schematic, or stick-figure, representation of the Poudre Basin, including the river mainstem and tributary inflows, all major irrigation diversions and storage facilities, and it identifies the priorities and amounts of the water rights associated with each facility.
A broader, insightful history of irrigation, settlement, and change in the Poudre Basin was written by Rose Laflin, and is available from the Colorado Water Institute, here: Laflin (2005). This report also includes an extensive glossary of water resources terminology, and the DWR provides a Water Rights Dictionary on its website. A separate report summarizing the history of development in the Poudre Basin is also being prepared for inclusion with the NISP and HSWSPs EISs. Additional reference materials that are not otherwise available as free downloads from state agencies, in particular memos and reports prepared for the NISP and HSWSPs EISs, are available upon request from USACE.
The foundation of water administration in Colorado is the Doctrine of Prior Appropriation, which, in the simplest terms, means "first in time, first in right." This concept is supplemented by more than 150 years of legislation, statutes, and case law at both the Division Water Court and Colorado Supreme Court levels. Within this memorandum, this foundational water law will be explained first, followed by an overview of historical and current flow conditions in the Poudre Basin. Subsequent sections of this memorandum will focus on the various factors influencing water administration in the Poudre Basin, including transbasin diversions, major municipal and industrial (M&I) water providers, major irrigation ditches, exchange operations, river dry-up points, and minimum flow points. This memorandum is intended to provide the reader a basic understanding of these topics in order to provide greater context for the extensive documentation associated with the NISP and HSWSPs EISs.
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Section 2 – Colorado Water Law This section provides a summary overview of the basics of Colorado Water Law and the water rights associated with the proposed NISP and HSWSPs.
2.1 The Doctrine of Prior Appropriation The administration of water in Colorado is governed by the Doctrine of Prior Appropriation. This system is prevalent throughout the western United States and arose in response to the general scarcity of water in the region. The basic premise is the principle of "first in time, first in right," in which the first person or entity (e.g., irrigation company, municipality, or industrial operation) to place an amount of water to beneficial use is given the first opportunity to use that water in perpetuity, provided the user obtains a water right.
The DWR (2011) website provides a simplified example of the "first in time, first in right" concept:
For example, assume three water-users exist on a stream system with adjudicated (court- approved) water rights totaling 5 cfs (cubic feet per second). The user with the earliest priority date has a decree for 2 cfs, the second priority has a decree for 2 cfs, and the third priority right has a decree for 1 cfs of water. When the stream is carrying 5 cfs of water or more, all of the rights on this stream can be fulfilled. However, if the stream is carrying only 3 cfs of water, its priority number 3 will not receive any water, with priority number 2 receiving only half of its 2 cfs right. Priority number 1 will receive its full amount of 2 cfs under this scenario. This process of allocating water to various water users is traditionally referred to as "Water Rights Administration," and is the responsibility of the Division of Water Resources.
This concept is demonstrated in Figure 2.
River
5 cfs 3 cfs
Figure 2. Example of Water Rights Administration by Priority (DiNatale 2008)
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A water right is a legal document, secured through a water court adjudication process, describing the holder's right to use water. Water rights decrees generally define the location of the point of diversion, the beneficial use or uses of the water, the appropriation (priority) date and administration number, and the rate of flow for a direct flow water right or the volume for a storage water right. Upon the initial demonstration of intent, the user can acquire a conditional water right; once an amount of water has actually been applied to the beneficial use, the user can return to water court to have the decree codified as an absolute water right. If an extended period of time elapses between the securing of the conditional and absolute water rights, the user must periodically return to water court in order to demonstrate that they are showing due diligence in their pursuit of actual beneficial use; failure to do so may result in the abandonment of the water right. Provisions in the Colorado Constitution dictate that the water within the state's boundaries is owned collectively by the people of Colorado. Thus, a water right only entitles its owner to the use of water at a particular time and place, not actual ownership of the water.
Points of diversion are usually a headgate location on a stream or river or a well drilled into an alluvial or bedrock aquifer. The list of allowable beneficial uses has evolved over time and now includes, but is not limited to, irrigation, mining, municipal, industrial, domestic, stock watering, snowmaking, fisheries, recreation, storage, commercial, augmentation, and many others. Direct flow water rights are generally allowed to use water up to an established flow rate in units of cfs, and most storage rights are defined in volumetric terms, such as AF of storage.
The appropriation or priority date reflects the date that the user first demonstrated the intent to apply the water to beneficial use. The Administration Number is a number developed by the DWR to provide a simple and efficient method of ranking decrees in the order of seniority. Each side of the decimal points represents days since December 31, 1849. The left side represents the number of days between December 31, 1849 and the latter of the Previous Adjudication Date and the Appropriation Date. If the right side is non-zero, it represents the number of days between December 31, 1849 and the Appropriation Date (DWR 2010b). The lower the Administration Number, the more senior the water right is relative to other water rights with large Administration Numbers. Examples of Adjudication Dates, Previous Adjudication Dates, Appropriation Dates, and Administration Numbers are provided in Table 1 in Section 2.2.
Generally, the earlier in time the priority date, the more senior the water right. For example, the most senior water right, i.e., the #1 Priority, in the Poudre Basin is held by the City of Fort Collins and has an appropriation date of June 1, 1860. This water right has a direct flow limit of 3.50 cfs and was acquired from the Yeager Ditch and transferred to the Fort Collins Pipeline diversion above the North Fork confluence in the early 1900s.
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In general, direct flow water rights in the Poudre Basin are more senior than storage rights, and Poudre Basin rights are in general more senior than those on the lower South Platte River downstream of the Poudre confluence. This relative seniority of Poudre Basin water rights is repeated similarly in the SPDSS memos documenting four major Poudre Basin irrigation companies (see Section 7.2), as follows:
Storage rights in the Cache la Poudre Basin are generally senior to the downstream storage rights on the South Platte River and are therefore able to divert, in priority, with respect to other active winter diversions. In normal years, calls from the South Platte do not affect administration in Water District 3, as water rights in the Cache la Poudre Basin are generally senior to South Platte River water rights.
According to the SPDSS Water District 3 memo (LRE 2004a), "Junior rights in the basin are considered to be rights higher than water district priority 97, corresponding to the North Poudre Canal's 614 cfs right (administration number 10989)." This water right has an appropriation date of February 1, 1880. The majority of the irrigation direct flow and storage water rights in the Poudre Basin were adjudicated in the late 1800s or early 1900s.
2.2 Water Rights Associated with NISP and HSWSPs The conditional water rights proposed for use by NISP and the HSWSPs are very junior in terms of priority of water rights in the Poudre Basin, as shown in Table 1.
Under the prior appropriation or priority system, water rights are filled in order of priority date as determined by the Administration Number, and senior water rights holders are entitled to diversion of their full supplies before the next downstream junior right can take water as long as the water can be placed to beneficial use. In the Poudre Basin, all existing major irrigation and storage diversions will be able to meet their needs before the proposed projects currently undergoing NEPA review will be allowed to make diversions under their junior conditional storage and exchange water rights.
Given the junior priorities of the water rights associated with the proposed projects in the context of existing Poudre Basin operations and administration, these junior rights would most likely be in priority and able to divert at times when the Poudre River is currently declared to be under "free river" conditions. As defined by Leak (2010), free river is "A term used to describe a condition where the flow of the river is sufficient to satisfy all vested [water] rights, and diversions from the river can be made without possibility of injury to any senior right."
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Table 1. Conditional Storage and Exchange Water Rights Proposed to be Used by NISP and the HSWSPs Adjudication Date Conditional Administration Reservoir Name (Previous Adjudication Appropriation Date Storage Volume Associated Project Number1 Date) or Flow Rate December 31, 1977 Seaman Reservoir Rockwell Reservoir October 31, 1951 46386.37193 4,900 AF (December 31, 1976) Enlargement3 Grey Mountain Dam and Reservoir (Glade December 31, 1980 May 2, 1980 47604.00000 220,000 AF NISP Reservoir)2 Cache la Poudre Forebay Reservoir (Glade December 31, 1980 May 2, 1980 47604.00000 5,400 AF NISP Reservoir Forebay) Halligan Reservoir aka North Poudre Reservoir December 31, 1985 Halligan Reservoir August 1, 1979 49308.47329 33,462 AF No. 16 (December 31, 1984) Enlargement3 December 31, 1990 Seaman Reservoir Milton Seaman Reservoir March 1, 1980 51134.47542 9,992 AF (December 31, 1989) Enlargement3 SPWCP Pumping Station, Forebay Reservoir, December 31, 1992 December 11, 1992 52210.00000 500 cfs NISP South Platte River Intake SPWCP Pumping Station and Forebay Reservoir December 31, 1992 December 11, 1992 52210.0000 400 AF NISP SPWCP Galeton Reservoir December 31, 1992 December 11, 1992 52210.0000 45,624 AF NISP Exchange, New Cache la Poudre Irrigating Company Canal, canal headgate (Greeley No. 2 December 31, 1992 December 11, 1992 52210.0000 250 cfs NISP Canal) Exchange, Larimer and Weld Irrigation Company December 31, 1992 December 11, 1992 52210.0000 500 cfs NISP Canal, canal headgate Exchange, Poudre Valley Canal, canal headgate December 31, 1992 December 11, 1992 52210.0000 400 cfs NISP 1 The Administration Number is a number developed by the DWR to provide a simple and efficient method of ranking decrees in the order of seniority. Each side of the decimal points represents days since December 31, 1849. The left side represents the number of days between December 31, 1849 and the latter of the Previous Adjudication Date and the Appropriation Date. If the right side is non-zero, it represents the number of days between December 31, 1849 and the Appropriation Date (DWR 2010b). 2 The NCWCD owns 7/8 of the Grey Mountain Dam and Reservoir water right. The remaining 1/8 share is owned by the Cache la Poudre Water Users Association. HSWSPs Applicants Fort Collins and Greeley have expressed interest in purchasing this 1/8 share to use with the proposed enlargements of Halligan Reservoir and Seaman Reservoir, respectively. 3 The Rockwell Reservoir and Milton Seaman Reservoir junior conditional storage rights do not represent all sources of water to be stored in the proposed enlargement of Seaman Reservoir. Applicant Greeley also plans to purchase senior agricultural water rights and transfer them for storage in Seaman Reservoir. Likewise, the junior conditional storage right for Halligan Reservoir is not the sole source of water for the proposed Halligan Reservoir enlargement; Applicant Fort Collins also plans to transfer or exchange agricultural water rights for storage in Halligan Reservoir.
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When such conditions exist, there are no senior rights placing a "call" (see Section 2.3.1) on the river. In the example associated with Figure 2 above, when the river is flowing at only 3 cfs, the senior Priority #1 places a call on the river requiring the curtailment of diversions by the two users with more junior water rights. A call affecting Water District 3 administration may be internal to the Poudre Basin, or it may be downstream on the South Platte River (Water Districts 1 and/or 64).
If there is no call, and the Water Commissioner declares the river to be under free river conditions, any water user can make direct flow or storage diversions regardless of priority and apply the diverted water to beneficial use. In the Poudre Basin, free river conditions most often occur during the high flow months associated with the spring snowmelt runoff in May and June.
2.3 Duties of the Water Commissioner Wolfe (2005) describes some of the major responsibilities of Water Commissioners, excerpted in the following sub-sections. The full document is available from the DWR website, here.
2.3.1 Record Keeping Record keeping responsibilities of the Water Commissioner includes maintenance of diversion records and documentation of river calls.
Diversion Records. A primary responsibility of water commissioners is to keep records of daily diversions of decreed water rights of ditches, canals, wells, reservoirs, and legal diversions from undecreed structures. — Daily records may be derived from recorder charts, daily observations, reports from ditch companies, and pump power records using a Power Consumption Coefficient. — Diversion records state the types of water diverted (e.g., river water, reservoir water, transmountain water, augmentation water, recharge water, exchange water). — These records are official permanent public records of the state and are used by courts of law, and for research and studies. River Calls. Water rights are administered according to relative priorities on the stream. Daily, the Water Commissioner determines "calls" on the river from water rights owners and fills as many as possible with the amount of water available in the stream. Interstate compact obligations must also be considered. Calls are written or verbal orders for river, reservoir, or transmountain water predicated on decreed water rights. — Water commissioners maintain daily records of river calls or demands for diversions. Content will vary between districts depending upon site-specific needs. — These records may include river index, diversions that are in priority, reservoir and transmountain deliveries, reservoir storage levels, weather data, and compact accounting.
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— The call records are also official permanent public records of the state and used for court cases, study references, documentation, and determination of the abandonment list.
2.3.2 Regulate Headgates This daily process includes adjustment of headgate settings to ensure delivery of the proper amount of water to a ditch. This process requires communications with appointed headgate personnel for each ditch or canal, or by the actual setting of the headgate by the water commissioner.
2.3.3 Distribute Storage Water This process of administering the release and proper distribution of reservoir or "storage" water to the reservoir owner or user involves daily calculations of river and reservoir water in the system for delivery and calculation of reservoir transportation charges (water lost during transit).
2.3.4 Distribute Transmountain Water Water Commissioners are tasked with distributing transmountain water, managing water imported from another river basin so it is distributed to the proper water user's ditch or reservoir. Transportation charges may need to be assessed to its delivery.
2.3.5 Delivery of Augmentation and Exchange Water Water Commissioners are responsible for the accounting and administration of augmentation plans per court decree and exchanges. The Water Commissioner must ensure that the water subject to augmentation or exchange is delivered at the proper time and amount to prevent injury to other users.
Records kept for an augmentation plan will include amounts and dates of water delivery, acreage taken out of production ("dried up"), number of wells covered within the augmentation plan, and amount and rate of pumping from the augmentation plans' wells.
2.3.6 Inspections Water Commissioners inspect dams, livestock water tanks, erosion control dams, small impoundments, headgate installations, measuring devices, wells, and structures and places of use associated with water court applications. This task includes the authority to enter private property.
2.3.7 Restriction Enforcement The duties of the Water Commissioner include three types of restriction enforcement.
For wells, restriction enforcement is the enforcement of compliance with permitted or decreed restrictions for acreage, pumping rate, or volume pumped.
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For ditches, Water Commissioners enforce compliance with proper headgate adjustments to control water deliveries. Enforcement may require locking a headgate to prevent illegal diversions. For dams, this entails the enforcement of compliance to restrictions of storage set by the state engineer for structural and/or safety reasons.
2.4 Interstate Compacts and Decrees Colorado is a headwaters state, meaning that several major river systems—the Arkansas, Colorado, Rio Grande, North Platte, South Platte, and Yampa—originate in the Rocky Mountains within the state's borders, then continue downstream across state and even international boundaries. As a result, water use in Colorado is affected by one international treaty, two U.S. Supreme Court decrees, one interstate agreement, and nine interstate compacts. A 2006 report summarizing the compacts and decrees is available from the DWR, here: DWR Compacts Summary. While the Poudre River is tributary to the South Platte River, the terms of the South Platte River Compact of 1923 between Colorado and Nebraska are such that water allocation is only impacted from the western boundary of Washington County eastward to the Colorado- Nebraska state line. This geographic area coincides with Water District 64 and is far downstream of the Poudre River confluence with the South Platte River.
Most of the agreements having the potential to impact water use in the Poudre Basin are those related to transbasin imports to the Poudre Basin. These include the two U.S. Supreme Court decrees, which allocate the waters of the North Platte River (Nebraska v. Wyoming, 325 U.S. 589 [1945], aka North Platte River Basin Decree) and Laramie River (Wyoming v. Colorado, 353 U.S. 953 [1957], aka Laramie River Decree), and the Sand Creek Memorandum of Agreement (MOA) between Colorado and Wyoming (Revised 1997). The provisions of these compacts and agreements, as they affect administration in the Poudre Basin, are described in the SPDSS Water District 3 memo. The Colorado River Compact of 1922 and the Upper Colorado River Compact of 1948 may also affect transbasin diversions, including the Grand River Ditch. Additional details regarding the provisions of these decrees and compacts can be found in the DWR report linked in the previous paragraph. Transbasin diversions into the Poudre Basin are discussed in Section 4 of this memorandum.
2.5 Recommended Further Reading Colorado water law is a very complicated topic, and an in-depth examination is beyond the scope of this memorandum. However, there are several existing Colorado water law summaries that have been written with the general public as the intended audience, and the reader is encouraged to seek out the following references:
The DWR website has a section dedicated to Water Rights. Also available from the DWR is a Synopsis of Colorado Water Law (Revised Edition, 2011). As stated in the preface, "This publication…has been popular with our customers
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since it was first published in 1989. Originally published for use by water commissioners in the field, the book gained popularity with the public for its ease of use and assistance in understanding water law in Colorado." The Colorado Foundation for Water Education (CFWE) published its Citizen's Guide to Colorado Water Law, 3rd Edition, in 2009. Hard copies must be purchased from CFWE ($8.00), but the electronic version can be viewed online for free. Section 4 of the 2004 Statewide Water Supply Initiative (SWSI) report describes the Legal Framework for Water Use. The full report, including this section, is available for download, here: CWCB Studies and Reports. Appendix B of the SWSI 2010 report provides an Overview of Colorado Water Law, and is available here: Appendix B - Overview of Colorado Water Law. Section 3 – Historical Streamflows To place the EIS impacts analyses in context, it is useful to review historical streamflows in the study area. The U. S. Geological Survey (USGS) and the DWR operate a number of streamflow gages in the Poudre Basin and on the South Platte River below the Poudre confluence. Five of these gage locations, identified in Table 2, are of particular interest for the hydrologic impacts analyses associated with the NISP and HSWSPs EISs. Gaged streamflows represent actual river conditions and reflect native streamflow originating from rainfall and snowmelt within the basin as well as the effects of transbasin imports, irrigation and M&I diversions, and other human activities.
Table 2. Streamflow at Key Gages on the Poudre and South Platte Rivers Average Annual Streamflow1 USGS Colorado DWR Period Of [AF] Gage Location Gage ID Code Record [WY] Period of WY 1950- WY 1980- ID Number Record 2005 2005 1885-1903, Poudre River at Mouth of 06752000 CLAFTCCO 1905-1909, 261,399 227,693 239,192 Canyon near Fort Collins 1911-2009 Poudre River at Lincoln St. 06752260 CLAFORCO 1976-2009 108,582 N/A 120,553 in Fort Collins Poudre River above Boxelder Creek, near 0675280 CLABOXCO 1980-2009 94,993 N/A 102,393 Timnath 1915-1919, Poudre River near Greeley 06752500 CLAGRECO 97,637 115,842 148,068 1925-2009 1902-1903, South Platte River at 06754000 PLAKERCO 1906-1912, 633,141 719,439 877,536 Kersey 1915-2009 1 Average annual streamflow values based on USGS historical gaged streamflow values, supplemented as necessary by DWR records from the CDSS HydroBase.
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Table 2 specifies the available period of record for each gage, in complete USGS water years (WY). A USGS WY is defined as the period starting on October 1 of one year and ending on September 30 of the following year (Laflin 2005). For example, WY 2010 began on October 1, 2009 and concluded on September 30, 2010. Table 2 also provides the average annual streamflow measured at each gage for the entire available study period as well as the following sub-periods critical to the EIS analyses:
WY 1950-2005, the full simulation period for the Poudre Basin Network (PBN) MODSIM model, run on a monthly time step. WY 1980-2005, the study period for which disaggregated daily time series data is being generated for use in the EIS resource impacts analyses. This period was selected based on the available period of record for the Boxelder Gage, as shown in Table 2.
The variability seen in the average annual streamflow volumes across the three periods of record can be at least partially explained by combined human and climatological/hydrological factors. At the Greeley and Kersey gages, in particular, the more recent study periods show substantially higher average annual flows than the result calculated for the full period of record at each gage. Possible reasons include the following:
The extended drought of the 1930s has the effect of lowering the overall average. The WY 1950-2005 averages are higher, but are lower than the most recent period due to the inclusion of the mid-1950s drought and the very dry year of 1977. The WY 1980-2005 period average is higher than the long-term average and likely skewed relative to the other longer-term averages due to the inclusion of the two of the wettest years on record in 1980 and 1983, as well as an extended wet period in the mid- 1990s. Perhaps most significant to the post-1950 flow increases is the startup of the Colorado- Big Thompson (C-BT) Project in the early 1950s. This project brought significant supplemental water to the Poudre Basin for agricultural and, increasingly, municipal purposes; C-BT water is delivered to the Poudre River, below the Canyon Gage, via the Hansen Supply Canal. The flow increases attributably to C-BT deliveries are not observed in the Canyon Gage, but are reflected in those gages downstream (see Sections 4.2 and 7.1). In addition to the added C-BT water, increased runoff from impervious urban areas and increased discharges of treated wastewater effluent also contribute to increased streamflow downstream.
Historical streamflow trends at the Canyon Gage are somewhat different, with the full period of record having the highest average annual streamflow, at 261,399 AF. Part of this is due to the Canyon Gage having a longer period of record than the other gages, as described by Laflin (2005), "The Poudre's Canyon Gaging Station was the first gaging station in the state and has been used
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continuously since 1883." The data used in the present analyses starts with WY 1885 because WY 1883 and 1884 has incomplete datasets. The period from 1885 through the mid-1920s had consistently higher flows than subsequent periods, with much more frequent occurrences of above-average streamflows. This trend can be clearly seen in Figure 3, and certainly contributes to the higher long-term average.
A likely major factor in the lower post-1950 streamflows at the Canyon Gage is the Munroe Gravity Canal (aka North Poudre Supply Canal), which was built as part of the C-BT Project. The canal's headgate is located above the confluence of the North Fork and the Poudre River mainstem, and has diverted an average of greater than 30,000 acre-feet per year (AFY) since 1954. Increased municipal diversions at the Fort Collins Pipeline and, more recently, through the Pleasant Valley Pipeline (PVP) may also contribute to lower flows at the Canyon Gage. In the more recent WY 1980-2005 period, the effects of these diversions are offset somewhat by the very high flows in 1980 and 1983 and throughout the 1990s.
One additional trend of note, particularly observable in the WY 1980-2005 data, is the decline in streamflow from the Canyon Gage to the Boxelder Gage, followed by a rebound at Greeley. The decline in the upper reach is attributable to the many large irrigation and M&I diversions. While there are additional ditches diverting between the Boxelder and Greeley Gages, including the New Cache Ditch, ditch and farm tailwater and subsurface return flows from upstream agricultural diversions as well as municipal wastewater effluent contribute significantly to flows in the lower Poudre River above the Greeley Gage. This pattern is also discussed in Section 7.1.
Figures 3 through 12 on the following pages include two representations of the historical flows recorded at each gage listed in Table 2. The first figure shows the annual flow volume for each year in the full period of record at each gage, along with lines representing the average annual flow volumes shown in Table 2. The second figure provides a hydrograph of average daily flow for each of the three periods of record. Note that the figures for the Kersey Gage also include lines for the 1976-2009 period to illustrate the effects of Chatfield Reservoir on South Platte River flows.
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Figure 3. Annual Flow Volume, Cache la Poudre River at Canyon Mouth
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Figure 4. Hydrograph of Average Daily Flows, Cache la Poudre River at Canyon Mouth
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Figure 5. Annual Flow Volume, Cache la Poudre River at Lincoln Street
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Figure 6. Hydrograph of Average Daily Flows, Cache la Poudre River at Lincoln Street
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Figure 7. Annual Flow Volume, Cache la Poudre River above Boxelder Creek
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Figure 8. Hydrograph of Average Daily Flows, Cache la Poudre River above Boxelder Creek
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Figure 9. Annual Flow Volume, Cache la Poudre River at Greeley
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Figure 10. Hydrograph of Average Daily Flows, Cache la Poudre River at Greeley
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Figure 11. Annual Flow Volume, South Platte River at Kersey
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Figure 12. Hydrograph of Average Daily Flows, South Platte River at Kersey
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Figure 11.Annual Flow Volume, SouthPlatte River at Kersey Figure 12.Hydrograph of AverageDaily Flows, South RiverPlatte Kerseyat
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Section 4 – Transbasin Diversions As was mentioned in the previous section, in addition to native precipitation and snowmelt originating within the basin, transbasin diversions contribute significantly to the water supplies available in the Poudre Basin. These imported supplies originate in the Colorado River, Laramie River, North Platte River, or Sand Creek basins and are delivered to the headwaters of the Poudre River upstream of the Canyon Gage through ditches or tunnels.
4.1 Transbasin Diversions into the Poudre Basin Headwaters Table 3 lists the transbasin diversions and their respective decreed flow rates, based on SPDSS Task 5 memoranda for the transbasin diversion structures.
Table 3. Transbasin Diversion Structures Delivering to the Poudre River Basin Importing Ditch or Tunnel Basin of Origin Decreed Flow Rate and Maximum Observed Daily Diversion 524.6 cfs; Grand River Ditch Colorado River 347.0 cfs maximum observed daily diversion 300 cfs; Laramie-Poudre Tunnel Laramie River limited by Laramie River Decree; tunnel design capacity = 1,000 cfs 300 cfs total, headgate + intercepted tributaries; Skyline Ditch Laramie River limited by Laramie River Decree 60.0 cfs (less than design capacity); Bob Creek Ditch Laramie River limited by Laramie River Decree N/A; Columbine Ditch Laramie River ditch operations ceased after WY 1956; limited by Laramie River Decree N/A; Deadman Ditch Laramie River no associated direct flow water rights; limited by Laramie River Decree 288 cfs; decreed under the Sand Creek Ditch System; 156.0 cfs maximum Wilson Supply Ditch Sand Creek observed daily diversion; limited by Laramie River Compact and Sand Creek MOA 28.0 cfs; Cameron Pass Ditch North Platte River subject to North Platte River Basin Decree; 12 cfs maximum observed daily diversion 340.0 cfs; Michigan Ditch North Platte River limited to 146 cfs; 88.0 cfs maximum observed daily diversion; subject to North Platte River Basin Decree
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Figure 13 is a map showing the locations of each of the transbasin diversions into the upper reaches of the Poudre River Basin.
Table 4 provides distributions of average monthly transbasin imports and average annual import volumes based on Colorado Decision Support System (CDSS) HydroBase data for WY 1950-2009; CDSS HydroBase records diversions through these structures as streamflows in October through September water years. State abbreviations for locating structure diversion records in the CDSS HydroBase are shown after the structure name, followed by DWR structure identification numbers in parentheses in a (Water District of origin/Water District 3) format.
Table 4. Monthly and Annual Transbasin Imports to Poudre Basin, WY 1950-2009 Laramie- Grand River Bob Creek Wilson Cameron Michigan Poudre Skyline Ditch Ditch Ditch1 Supply Ditch2 Pass Ditch Ditch Tunnel SKYDCLCO GRNDRDCO BOBGLNCO WSDEARCO CAPDCPCO MICDCPCO Month LAPTUNCO (4800577/ (5104601/ (4800573/ (7600600/ (4704602/ (4704603/ (4800576/ 0304605) 0304601) 0304606) 0304604) 0304602) 0304603) 0304600) [AF] [AF] [AF] [AF] [AF] [AF] [AF] Oct 28 16 0 0 0 0 51 Nov 0 0 0 0 0 0 31 Dec 0 0 0 0 0 0 20 Jan 0 0 0 0 0 0 14 Feb 0 0 0 0 0 0 11 Mar 0 0 0 0 0 0 10 Apr 10 23 0 0 5 0 19 May 1,383 2,557 68 111 1,092 3 237 Jun 7,974 4,912 634 112 846 74 980 Jul 6,136 5,795 484 2 90 29 615 Aug 1,897 2,176 20 0 3 0 201 Sep 368 341 3 0 0 0 90 TOTAL 17,796 15,819 1,210 226 2,037 105 2,280 1 Bob Creek Ditch average deliveries are based on records for water years 1950-1956 and 1998-2009. The ditch was not in operation for the period of water years 1957-1997 (LRE 2005a). 2 Includes Deadman Ditch (7600530/0304608).
Summaries of each transbasin diversion into the Poudre Basin headwaters are provided below, excerpted from the SPDSS Water District 3 memo, and edited for content.
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Figure 13. Transbasin Diversions to the Poudre River Basin
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RiverBasin
sions to the Poudre
TransbasinDiversions to the PoudreRiverBasin
. .
3
Figure 1 Figure 13.Transbasin Diver
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4.1.1 Grand River Ditch The Grand River Ditch diverts water from the Colorado River to Long Draw Reservoir, then releases as needed for diversion through the Larimer County Ditch. It is owned by the Water Supply and Storage Company (WSSC). About 90 percent of the storage in Long Draw Reservoir is imported water from the Grand River Ditch; the remaining is stored by exchange for water in WSSC's lower reservoirs. Additional details about the operations of the Grand River Ditch are available here: Task 5 – Key Structure, Grand River Ditch (LRE 2004b).
4.1.2 Laramie-Poudre Tunnel The Laramie-Poudre Tunnel diverts water from the Laramie River to the Poudre River. It is owned roughly 2/3 by WSSC and 1/6 each by the City of Greeley and the Tri Districts (Fort Collins-Loveland Water District [FCLWD], East Larimer County Water District [ELCO], and North Weld County Water District [NWCWD]); the City of Greeley and the Tri-Districts recently purchased 1/3 of the tunnel interest from the Larimer and Weld Irrigation Company and evenly split the asset. Diversions are limited by the Laramie River Decree. Most years, as noted below, Skyline Ditch water is diverted through the tunnel; therefore, deliveries are generally 86 percent WSSC and 7 percent each to the City of Greeley and the Tri-Districts. Additional details about the operations of the Laramie-Poudre Tunnel are available here: Task 5 – Key Structure, Laramie Poudre Tunnel (LRE 2004c).
4.1.3 Skyline Ditch Skyline Ditch diverts water from the Laramie River Basin into the Poudre River Basin. The ditch is owned by WSSC. Water is delivered for use and storage through the Larimer County Ditch. Diversions are limited by the Laramie River Decree. Skyline Ditch rights can be delivered via Skyline Ditch or Cameron Pass Ditch and stored in Chambers Lake. Most years, Skyline Ditch rights are delivered through the Laramie Poudre Tunnel. These deliveries are not accounted for separately from WSSC Laramie-Poudre Tunnel rights. Additional details about the operations of the Skyline Ditch are available here: Task 5 – Key Structure, Skyline Ditch (LRE 2004d).
4.1.4 Bob Creek Ditch Bob Creek Ditch diverts water from the Laramie River Basin to the Poudre River Basin. The ditch is owned by the City of Greeley. Bob Creek Ditch diversions are limited by the Laramie River Decree. Columbine Ditch, also owned by the City of Greeley, diverted from the Laramie River Basin to the Poudre River Basin from the 1930s until 1956, but no longer diverts. Additional details about the operations of Bob Creek Ditch are available here: Task 5 – Key Structure, Bob Creek Ditch (LRE 2005a).
4.1.5 Deadman Ditch and Wilson Supply Ditch Deadman Ditch diverts water from the Laramie River Basin into Sand Creek, which is also tributary to the North Platte River in Wyoming. The water is then re-diverted by the Wilson Supply Ditch and brought through an open canal into Sheep Creek, which is tributary to the North Fork of the Poudre River. Water from Sand Creek can also be diverted through the Wilson Supply
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Ditch. The Wilson Supply Ditch has a decree for 288 cfs, with a priority date of June 15, 1899, that is recorded under the Sand Creek Ditch System.
Water diverted through the Wilson Supply Ditch into Sheep Creek is stored in Worster Reservoir. The Divide Canal and Reservoir Company previously owned Worster Reservoir, also known as Eaton Reservoir. The Divide Canal and Reservoir Company is a separate company from the Larimer and Weld Irrigation Company, but shares in both companies are held by irrigators under the Larimer Weld Irrigation Canal. Worster Reservoir was recently purchased by the Tri-Districts. However, according to Tri-Districts Water Resources Manager Shawn Hoff, "This change will not cause a re-operation from the historical operations of Worster Reservoir for the reasonabl[y] foreseeable future" (personal communication, 02/07/2011). Additional details about the operations of Wilson Supply Ditch are available here: Task 5 – Key Structure, Wilson Supply Ditch (LRE 2004e).
4.1.6 Cameron Pass Ditch The Cameron Pass Ditch diverts water from the Middle Fork of the Michigan River in the North Platte River Basin to the Poudre River Basin. The ditch is owned by WSSC. Water is delivered for use and storage through the Larimer County Ditch or stored in Chambers Lake. Additional details about the operations of the Cameron Pass Ditch are available here: Task 5 – Key Structure, Cameron Pass Ditch (LRE 2004f).
4.1.7 Michigan Ditch Michigan Ditch diverts water from the Michigan River in the North Platte River Basin to Joe Wright Reservoir, aka Mountain Supply Reservoir 20, in the Poudre River Basin. The ditch is owned by the City of Fort Collins, which completed rehabilitation work on the ditch between 1977 and 1986. Today, almost half of the ditch is piped. Additional details about the operations of Michigan Ditch are available here: Task 5 – Key Structure, Michigan Ditch (LRE 2004g).
4.2 Colorado-Big Thompson Project The C-BT Project—owned by the U.S. Bureau of Reclamation and operated by NCWCD—is also a key source of supplemental water supply for many Poudre Basin water users. This transbasin project collects flow from the headwaters of the Colorado River and delivers it through a series of canals, tunnels, and pipelines to the Big Thompson River Basin and then also to Carter Lake and Horsetooth Reservoir. Horsetooth Reservoir, located directly west of Fort Collins, is a primary terminal storage facility for C-BT water. From Horsetooth Reservoir, water is delivered to the Poudre River mainstem via the Hansen Supply Canal. The Hansen Supply Canal delivery point is near Bellvue, just below the Canyon Mouth, Poudre Valley Canal (PVC), and the Greeley Filters Pipeline intake, but upstream of the Larimer County Canal. The Windsor Extension delivers C-BT water directly to the PVC.
C-BT water is delivered to allottees based on an annual quota per unit of ownership; C-BT water differs from other transbasin water in that owners are entitled to one-time use only. There are a
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total of 310,000 units issued for the C-BT Project, with a yield of 1.0 AF of water per unit per year at 100 percent quota. Actual yield varies depending on hydrologic conditions in the source basin (Upper Colorado) and delivery basin (South Platte), with a yield quota that generally varies between 0.5 AF/unit and 1.0 AF/unit. The historical average yield for C-BT is approximately 0.7 AF/unit, with a firm yield of 0.6 AF/unit (MWH 2004, Pineda 2005).
Historically, C-BT water was used predominantly for agriculture, but municipal ownership and use has increased over the original municipal ownership, and the trend of increased municipal use and ownership continues. Riverside Technology, Inc. (RTi 2005a, b) states:
Perhaps the most significant change occurring in the Poudre Basin is the transfer of C-BT water from agricultural ownership to municipal ownership. To date, the effects of this transition have not been fully appreciated as municipal owners have continued to rent a substantial amount of C-BT water back to agricultural users. As municipal demands increase, their ability to support agriculture through the rental market will be diminished…
According to Pineda (2009), "The number of [C-BT] units that has changed from Ag irrigation to M&I ownership has averaged 3,569 units per year. This number does not include units that are part of the 40,000 units of the…NPIC contract." Overall M&I ownership surpassed agricultural ownership starting in the late-1990s (see Pineda 2009, Figure A.1).
In NISP (Phase II) Technical Memorandum No. 6C (Gibbens 2006), it was estimated for 2003 baseline conditions that overall ownership was split approximately 60 percent M&I, 40 percent agricultural, while actual deliveries the exact opposite due to leaseback and/or rental programs by M&I users with large C-BT holdings. By 2008, these figures changed to 72 percent M&I ownership (including NPIC M&I C-BT units, which account for 8 percent) and 28 percent agricultural ownership, with deliveries still similar to earlier in the decade at 41 percent to M&I users and 59 percent to agricultural users as a result of leasing from M&I owners to agricultural users (Pineda 2009).
C-BT water for both M&I and agricultural purposes is delivered to the Poudre River Basin from Horsetooth Reservoir. The M&I deliveries are generally released directly from storage to the Fort Collins and Tri-Districts water treatment plants below the Soldier Canyon Dam, and to Greeley's Bellvue water treatment plant through a direct connection from the Hansen Supply Canal in summer (April – October) or through the PVP in winter. As a result, deliveries of C-BT water to Poudre Basin M&I users generally do not affect river flows in the Poudre Basin. However, deliveries of C-BT agricultural water occur directly into the Poudre River from the Hansen Supply Canal or through the Windsor Extension to the PVC. As stated by Pineda (2009), "There has been a general decline in the volume of Ag deliveries since 1957. Deliveries of C-BT water for agricultural purposes to the Poudre River has averaged 70,000 [AFY] from 1957-2008." This volume of supplemental water deliveries corresponds to some of the post-1950 flow increases at the Greeley and Kersey Gages, as described in Section 3 above.
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Figure 14 illustrates the historical time series of Hansen Supply Canal releases to the Poudre River by incorporating data from the HSCCLPCO gage reported in the CDSS HydroBase for WY 1952-1999 and the Hansen Supply Canal 20’ Flume reported on the NCWCD website for WY 2000-2009. Based on these records, C-BT deliveries to the Poudre River have averaged nearly 75,700 AFY over WY 1952-2009. The Windsor Extension, which releases C-BT water directly to the PVC and does not contribute to Poudre River flows, delivered an average of nearly 4,600 AFY over the period including WY 1954-1999, measured at the HSCPVDCO gage.
Although the C-BT deliveries to the Poudre River average nearly 75,700 AFY based on the reported gage data, Figure 14 clearly shows the downward trend in deliveries over time. In comparison, simulated C-BT deliveries to Poudre Basin agricultural users based on NISP/HSWSPs Common Technical Platform (CTP) current conditions modeling have an average annual volume of about 54,500 AFY, as shown in Table 5. Current conditions are defined as the year 2010 for the CTP modeling, which is used to provide a common baseline for the evaluation of project impacts to the Poudre River for the NISP and HSWSPs EISs.
Table 5. Average Annual Simulated C-BT Deliveries to Poudre Basin Agricultural Users, 1950-2005 CTP Current Conditions Entity [AFY] New Cache 2,386 NPIC 16,759 WSSC 5,481 Larimer and Weld 26,431 Pleasant Valley and Lake Canal 3 South Side Ditches (Arthur, New Mercer, Larimer No. 2) 1,532 Lake Canal 1,516 Total 54,467
Historically, the C-BT Project released 'non-charge' water, which was administered by the Water Commissioner as river water and was not charged against that year's delivery quota when diverted by C-BT allottees. Non-charge releases occurred when the C-BT Project storage was full or anticipated to fill and additional water was available for diversion into C-BT Project facilities. The CDSS HydroBase structure summary report for the Hansen Canal (Structure ID 0300909) shows the following "CBT NON-CHARGE ADMINISTERED AS RIVER WATER" in the diversion comments:
1995 = 22,381 AF 1996 = 22,381 AF 1997 = 39,064 AF 1998 = 23,898 AF
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Figure 14. C-BT Releases to Poudre River via Hansen Supply Canal, WY 1952-2009 (Source: CDSS HydroBase, HSCCLPCO gage for WY 1952-1999 and Hansen Supply Canal 20’ Flume flow data from NCWCD website for WY 2000-2009)
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This is a very limited record, but it does give an idea of the magnitude of historical C-BT non-charge releases to the Poudre Basin. It is not known whether this program will continue into the future. However, through discussions with NCWCD staff during the CTP hydrologic model development process, it was determined that a program called the 'Poudre Block' would operate in a similar, though reduced, manner as the non-charge water. Simulated deliveries of 'Poudre Block' water are made primarily in October and average approximately 4,200 AFY in the current conditions (2010) modeling and approximately 3,200 AFY in the future conditions (2050) modeling.
Additional information about the C-BT Project deliveries to the Poudre River Basin is available from the following sources:
Task 5 – Key Structure, Northern Colorado Water Conservancy District and Colorado-Big Thompson Project (LRE 2006a). NISP/HSWSPs CTP Model Review Report, Appendix A, Section A-3.0 C-BT Deliveries to Poudre River (Camp Dresser & McKee Inc. [CDM] 2011). Memorandum, Projection Tool Development for C-BT Project Operations for the NISP- HSWSP Common Technical Platform Hydrologic Analysis (Pineda 2009). NISP Technical Memorandum No. 4 Colorado-Big Thompson Operation in the Poudre River MODSIM Network (Carney and Baldo 2005a). Section 5 – Mountain Water Supply Systems Many Poudre Basin water users have storage facilities high in the mountains. Those facilities are described in the following sections. In addition, the Joint Operations Plan (JOP) that involves several high mountain reservoirs is described. Note that for discussion of reservoir properties, "active capacity" is defined as total reservoir storage volume minus the dead storage volume. Dead storage applies to volume that is either below the reservoir outlet and therefore cannot be released from storage, or it is reservoir space that has been filled in with sediment. The active reservoir capacities reported herein were sourced either directly from SPDSS memos or calculated from total and dead storage reported in the SPDSS memos, depending on which information was available.
5.1 High Mountain Reservoirs Closely tied to the transbasin diversions described in Section 4 is the network of high mountain reservoirs owned by M&I and agricultural water providers in the Poudre River Basin. These include the following reservoirs owned and operated by City of Greeley:
Barnes Meadow Reservoir (active capacity = 2,349 AF), an off-channel reservoir on Barnes Meadow Creek, a tributary to Joe Wright Creek, which is in turn tributary to the mainstem of the Poudre River.
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Comanche Reservoir (active capacity = 2,629 AF), an on-channel reservoir on Big Beaver Creek. Hourglass Reservoir aka Big Beaver Reservoir (active capacity = 1,693 AF), an off-channel reservoir on Hourglass Creek, a tributary to Big Beaver Creek. Twin Lake Reservoir (active capacity = 278 AF), an off-channel reservoir on Pennock Creek, a tributary of the South Fork of the Poudre River. Peterson Lake (active capacity = 1,183 AF), an off-channel reservoir adjacent to Poudre River, located north of Long Draw Reservoir and southeast of Chambers Lake and Barnes Meadow Reservoir.
As stated in the SPDSS Greeley memo (LRE 2006b), "The City [of Greeley] purchased Barnes Meadow Reservoir and four other high mountain reservoirs from the Mountain and Plains Reservoir Company in 1947 to provide additional late-summer water supplies."
The City of Greeley is also a party to the JOP with the City of Fort Collins and WSSC. This plan was developed in coordination with the U.S. Forest Service (USFS), and is described in greater detail in Section 5.3 of this memorandum. To meet its obligations under the JOP, the City of Greeley makes winter releases from Barnes Meadow Reservoir or, by exchange, from WSSC's Chambers Lake. Additional information is available here: Task 5 – Key Municipal User, City of Greeley (LRE 2006b).
The City of Fort Collins owns Joe Wright Reservoir, which has an active capacity of about 6,474 AF (based on total capacity of 7,161 AF and 687 AF of dead storage) and can be used to store transbasin water diverted through the Michigan Ditch from the Michigan River in the North Platte River Basin. According to the SPDSS Fort Collins memo (LRE 2005b), "The City [of Fort Collins] purchased these supplies from [NPIC] in 1971 and enlarged Joe Wright Reservoir in the late-1970s. Water supplies associated with the 1971 Joe Wright Reservoir enlargement decree are reusable; the City of Fort Collins uses this reusable water through its participation in a 3-way agreement (Reuse Plan) with the Platte River Power Authority and WSSC. The City of Fort Collins also uses water stored in Joe Wright to meet its obligations under the JOP. Additional information regarding the operation and administration—in particular the Reuse Plan and JOP—of Joe Wright Reservoir is available here: Task 5 – Key Municipal User, City of Fort Collins (LRE 2005b).
In addition to its transbasin diversion structures described in Section 4, WSSC owns two mountain reservoirs: Long Draw Reservoir and Chambers Lake. Long Draw Reservoir, with active storage of 10,625 AF, is located high on La Poudre Pass Creek near the Continental Divide and stores transbasin water supplies diverted through the Grand River Ditch. Chambers Lake is located on Joe Wright Creek, about 3 miles downstream of the Joe Wright Reservoir outlet. Active storage in Chambers Lake is 8,824 AF, which is used to store transbasin water diverted through Cameron Pass, Michigan Ditch, and Skyline Ditch.
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WSSC transmountain water is generally diverted and stored between May 15 and July 1. Chambers Lake makes winter releases as part of the JOP. As stated in the SPDSS WSSC memo, "Releases from Long Draw Reservoir and Chambers Lake are officially charged a delivery loss of 1/10th of 1 percent per mile. For ease of administration, this delivery loss is approximated as a flat 5 percent of total release." Additional information regarding the operation and administration of these two reservoirs can be found in the SPDSS WSSC memo, available here: Task 5 – Key Structure, Water Supply and Storage Company (LRE 2005c).
Worster Reservoir, which was recently acquired by the Tri-Districts from the Divide Canal and Reservoir Company (see Section 4.1.5), has active storage of at least 3,750 AF. Worster Reservoir stores transmountain water diverted through the Wilson Supply Ditch and releases to the North Fork of the Poudre River and Halligan Reservoir as part of an exchange operation with NPIC. NPIC then delivers a like amount of C-BT water for use by the Divide Reservoir and Canal Company shareholders. Additional information is available in the SPDSS Larimer and Weld memo, here: Task 5 – Key Structure, Larimer and Weld Irrigation Company (LRE 2005d).
5.2 Halligan Reservoir and Milton Seaman Reservoir Halligan Reservoir and Milton Seaman Reservoir are existing on-channel storage facilities located on the North Fork of the Poudre River. Each reservoir is proposed for expansion by its owners; the proposals are currently undergoing NEPA review, and this memorandum is part of the supporting documentation for the HSWSPs EIS.
Halligan Reservoir, aka North Poudre Reservoir No. 16, was built and operated by the NPIC. It is located approximately 8 miles south of the Colorado-Wyoming state line and approximately 25 miles northwest of Fort Collins. It has an active storage capacity of 6,428 AF. According to the SPDSS NPIC memo (LRE 2005e), "Storage water in Halligan Reservoir is generally used for regulation of water in the NPIC System, irrigation of lands within the NPIC system, storage of M&I water, and for exchange purposes." Historically, NPIC begins filling its reservoirs immediately following the end of the irrigation season, around November 1. Due to its location high in the Poudre Basin and high in the NPIC system, Halligan Reservoir is generally the first of NPIC's many reservoirs to be filled. As noted, Halligan Reservoir is also involved in a water exchange with Worster Reservoir and stores Worster water in exchange for C-BT.
The SPDSS Fort Collins memo further explains that the city needed additional storage capacity to help meet return flow obligations, provide carryover storage, and enhance the flexibility within its water resources system. As a result, "The City [of Fort Collins] purchased Halligan Reservoir…from NPIC in 2003 to address these needs. Under the terms of the purchase agreement, [if] the Halligan Reservoir enlargement is completed, NPIC will retain ownership of the original capacity plus an additional 5,000 AF of the enlargement. The next 12,000 [AF] of storage water (stored under absolute and conditional water rights) will go to Fort Collins…" As shown in Table 1, the junior conditional storage right for the expansion of Halligan Reservoir is for 33,462 AF.
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The following additional operations are unique to the Halligan Reservoir and the North Fork:
NPIC has historically drained Halligan Reservoir as a means of flushing accumulated sediment within the reservoir. Flushing releases have been done on a limited, as-needed basis. NPIC currently makes winter releases from Halligan Reservoir to help maintain the CWCB junior decreed minimum flows below the reservoir in the North Fork (LRE 2005d). This is a year-to-year agreement that allows Fort Collins to store up to 500 AF of fully- consumable water in Halligan Reservoir during the irrigation season, transferred from the South Side Ditches. This stored water is then released down the North Fork at a rate of approximately 3 cfs through the winter months.
Further details regarding the water rights, operation, and administration of Halligan Reservoir are available here: Task 5 – Key System, North Poudre Irrigation Company (LRE 2005d).
The City of Greeley owns Milton Seaman Reservoir, located on the North Fork of the Poudre River about a mile upstream of the North Fork's confluence with the Poudre River mainstem. The existing reservoir has an active capacity of 4,208 AF (based on 5,008 AF total storage and 800 AF dead storage) with a junior conditional storage right for the expansion of Milton Seaman Reservoir of 9,992 AF of storage right, as shown in Table 1. According to the SPDSS Greeley memo (LRE 2006b), "The city generally stores water in Milton Seaman Reservoir during the winter under the upstream storage statute against the senior downstream Timnath Reservoir storage right. Water stored out of priority during the winter is then released during the spring if Timnath Reservoir or other downstream, senior storage rights do not fill." Additional information about the water rights, operations, and administration of Milton Seaman Reservoir are available in the SPDSS Greeley memo, here: Task 5 – Key Municipal User, City of Greeley (LRE 2006b).
5.3 Joint Operations Plan Descriptions of the JOP are scattered across the SPDSS Fort Collins, Greeley, WSSC, and Water District 3 memos, all linked above. The basis for the plan is described as follows:
Fort Collins, Greeley, and WSSC [previously required] special use permits from the USFS to operate their reservoirs [Joe Wright, Barnes Meadow and Peterson Lake, and Long Draw, respectively] on public lands. Bypass flow requirements are often required by the USFS as a condition of issuing special use permits. Concerned with the potential loss of yield from needing to make bypass releases from their storage units, these entities worked with the USFS to develop the JOP, under which all entities are able to benefit. [The JOP was eventually selected as the preferred alternative and the USFS issued a Records of Decision (ROD) approving the JOP and granting 50-year easements for the Fort Collins, Greeley, and WSSC reservoirs.]
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The operations of Fort Collins, Greeley, and WSSC have changed since winter 1994-1995 under the JOP. The winter operations of these entities were modified to meet the objective of releasing 10 cfs down the Cache la Poudre River to the canyon mouth over the November 1 through March 31 period:
Greeley releases 7 cfs from its Barnes Meadow Reservoir or WSSC's Chambers Lake; Fort Collins releases 3 cfs from its Joe Wright Reservoir or WSSC's Chambers Lake.
The SPDSS Fort Collins memo adds details pertinent to the city's operations:
[The City of Fort Collins is] required to pass the lesser of 1 cfs or the natural inflows through Joe Wright Reservoir during the winter. In addition, under the JOP, Fort Collins moves 600 [AF] of storage water from Joe Wright Reservoir to Chambers Lake before the end of October. The transferred storage water is used to make up the remaining 2 cfs of delivery over the winter months for Fort Collins. The use of Chambers Lake by either of the municipalities is provided for by WSSC. The City of Fort Collins diverts its 3 cfs at the [Fort Collins] Pipeline. The City of Greeley diverts its 7 cfs at the Bellvue Filter Plant. [Note that in 2001, the City of Fort Collins acquired the land under and around Joe Wright Reservoir through a land exchange with the USFS. Fort Collins also granted a conservation easement to the United States of America providing for year round minimum flows—consistent with the JOP— immediately below Joe Wright Reservoir.]
Likewise, the SPDSS Greeley memo emphasizes that City's operational aspects:
The annual yield to Greeley from its Barnes Meadow Reservoir system is generally insufficient to satisfy the winter releases under the JOP (approximately 2,100 [AFY]). Any demand not met from Barnes Meadow is facilitated by releases from WSSC's Chambers Lake Reservoir. Greeley pays WSSC back for WSSC's winter storage contribution to the JOP on a one-to-one basis with transbasin water in Horsetooth Reservoir.
The releases and diversions made under the JOP are coordinated with Water Commissioner George Varra. The water that is released from the participating entities' high mountain reservoirs provides beneficial instream flows during the winter; however, the water is not decreed for this purpose. From an administrative perspective, it is therefore important that the winter flows released from the high mountain reservoirs are diverted downstream and applied to beneficial use, per the requirements of Greeley's and Fort Collins's water rights.
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Section 6 – Major M&I Water Providers in the Poudre Basin The Cities of Fort Collins and Greeley, along with the Tri-Districts, are the largest providers of M&I water in the Poudre Basin.
6.1 Fort Collins and Greeley Pipelines Table 6 provides average annual M&I diversions by Greeley and Fort Collins into their pipelines from the Poudre River. These diversions include all water sources diverted at the pipeline intakes (and recorded in the CDSS HydroBase) but do not include the cities' C-BT water released from Horsetooth Reservoir. C-BT water delivered to Fort Collins is released directly into the city's water treatment plant; Greeley's C-BT water can be delivered to the Bellvue Filter Plant through a turnout from the Hansen Supply Canal in summer (April-October) or through the PVP in winter. Note that M&I and agricultural diversions are reported in the CDSS HydroBase on an irrigation year (IY) basis, which is shifted one month relative to the water years used for reporting streamflows (see Section 3). The administrative IY begins on November 1 and ends October 31.
Table 6. Greeley and Fort Collins M&I Pipeline Diversions from the Poudre River Average Annual Average Annual Average Annual DWR Decreed Diversion, Diversion, Diversion, Diversion Structure Structure Amount1 IY 1950-2009 IY 1950-2005 IY 1980-2005 ID Number [cfs] [AFY] [AFY] [AFY] Greeley Filters Pipeline2 0300908 28 13,719 13,314 16,452 Fort Collins Pipeline 0300906 32.47 10,219 9,992 12,240 1 Decreed amounts based on water rights records (sum of absolute rates) downloaded from CDSS HydroBase on 07/11/2011 (Greeley) or specified by entity (Fort Collins); physical capacities of pipelines may vary from the stated flow rates. 2 Recorded diversion values account for all sources of water entering the Bellvue Filter Plant, including C-BT water.
The cities' water use has increased steadily from the 1950s to the present as the result of the increase in water demand and greater exercise of the direct flow water rights. This is illustrated in Figure 15, which is based on CDSS HydroBase historical diversion records for the Fort Collins Pipeline (Structure ID 0300906) and the Greeley Filters Pipeline (Structure ID 0300908) for IY 1950-2009.
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Figure 15. Greeley and Fort Collins1 Pipeline Diversions from the Poudre River, IY 1950-2009 (Source: CDSS HydroBase) 1 Fort Collins pipeline did not divert from September 1987 through May 1988, November 1998 through March 1999, and November 2005 due to maintenance. The pipeline also reduced diversions in 2004 and 2005 for testing of the PVP.
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As shown in Figure 15, there are several years in which there are significant drops in Fort Collins' diversions through its pipeline. The reasons for these drops are as follows:
1988 – The pipeline was shut down from 9/18/87 through 6/3/88 to switch from treating water at the old Fort Collins treatment plant near the diversion to delivering it to the new Fort Collins water treatment plant at Horsetooth Reservoir. 1999 – The pipeline was shut down from 11/2/98 through 3/23/99 due to failure in a section of the pipeline. 2004 and 2005 – The pipeline was shut down from 10/5/05 through 11/1/05, but most of the drop in diversions can be attributed to Fort Collins diverting more water into the PVP (see Section 6.3) so the treatment plant could test operating with that pipeline.
Additional information regarding the water supply system and operations of the City of Fort Collins is available here: Task 5 – Key Municipal User, City of Fort Collins (LRE 2005b), and for the City of Greeley, here: Task 5 – Key Municipal User, City of Greeley (LRE 2006b).
6.2 Tri-Districts The Tri-Districts (FCLWD, ELCO, and NWCWD) collectively treat the individual districts' water supplies in a common water treatment plant known as the Soldier Canyon Filter Plant (SCFP), which has a direct connection along with the City of Fort Collins into Horsetooth Reservoir. It is also connected by pipeline to the Poudre River, sharing the PVP connection with Fort Collins and Greeley.
The Tri-Districts currently rely primarily on C-BT units for the majority of their supply. They have rights in the NPIC and take their NPIC yield primarily as C-BT units. In addition, the Tri-Districts have transmountain water supplies from the Sand Creek Basin, which are diverted to the Poudre Basin through the Wilson Supply Ditch and delivered to the SCFP by exchange to the Munroe Canal diversion and the PVP.
Fort Collins, Greeley, and the Tri-Districts do not account for all M&I use in the Poudre Basin. Although these three entities are the largest, there are many other smaller municipalities and rural domestic water providers in the basin. In addition, industrial enterprises such as Kodak (near Windsor) and the Anheuser-Busch brewery northeast of Fort Collins use substantial quantities of Poudre River water each year. Note that Anheuser-Busch is not self-supplied; the brewery is a large contractual user and receives a combination of reusable and single-use potable supplies from Fort Collins, which are reflected in the city's M&I diversions.
6.3 Pleasant Valley Pipeline Construction of the PVP was completed in spring 2004 to supplement existing M&I diversions and to provide greater system operational flexibility for Fort Collins, Greeley, and the Tri- Districts. The PVP uses the Munroe Canal headgate as the point of diversion from the Poudre
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River, and the pipeline intake withdraws from the Munroe Canal. The SPDSS Fort Collins memo describes the new pipeline as follows:
Fort Collins, Greeley, and the Tri-Districts finished construction of the 120-[million-gallons- per-day] mgd (186 cfs) capacity [PVP] in spring 2004. The PVP conveys water from the North Poudre Supply Canal (aka Munroe Gravity Canal) past Greeley's treatment plant near Bellvue en route to the City of Fort Collins and the Tri-Districts treatment plants at Horsetooth Reservoir…The PVP is intended to provide river water to the Fort Collins [Water Treatment Facility] WTF (60-mgd capacity) and the Soldier Canyon Treatment Plant (60-mgd capacity) during the summer (April-October) and be used in the reverse direction to provide storage water from Horsetooth Reservoir to the City of Greeley's Bellvue Treatment Plant during the winter (November-March).
For the available period of record since PVP operations began (IY 2004-2009), M&I diversions through the PVP from the Poudre River via the Munroe Canal have averaged 5,059 AFY, with a minimum of 2,318 in 2006 and a maximum of 9,874 AF in 2005. These diversions are recorded in the CDSS HydroBase under the Munroe Canal (Structure ID 0300905), coded as S:6 (combined) and U:2 (municipal). Section 7 – Major Irrigation Water Users in the Poudre Basin The following sections describe average annual agricultural diversions from the Poudre River as well as several of the largest irrigation companies in the basin.
7.1 Average Annual Diversions for Agriculture Agriculture has long been the dominant user of water in the Poudre Basin. Historical average diversions for 22 major irrigation ditches over the period encompassing WY 1950-2009 and subsets of years related to the NISP and HSWSPs EIS modeling are provided in Table 7. The ditches and canals included in Table 7 are listed in upstream-to-downstream order; the CDSS HydroBase is the data source.
The combined average annual diversions for these 22 ditches total 405,075 AFY for the full available period of record, IY 1950-2009. There are other small ditches within the Poudre Basin, including several diverting from the North Fork and other tributary streams, but those ditches and canals identified in Table 7 account for the majority of all irrigation diversions. The recorded diversions for each ditch include all sources, including native river water, transbasin imports, C-BT water, exchanges, and diversions to storage.
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Table 7. Major Poudre Basin Irrigation Diversions Average Average Average DWR Decreed Annual Annual Annual Ditch Structure Amount1 Diversion, Diversion, IY Diversion, IY ID Number [cfs] IY 1950-2009 1950-2005 1980-2005 [AFY] [AFY] [AFY] North Poudre Canal 0300994 715.03 30,671 30,859 33,983 Munroe Gravity Canal (aka North 0300905 250 34,137 34,137 31,204 Poudre Supply Canal)2 Poudre Valley Canal 0300907 29.51 15,781 16,232 17,631 Pleasant Valley & Lake Canal 0300910 137.93 13,725 13,923 11,711 Larimer County Canal 0300911 750.01 70,726 71,496 65,412 Dry Creek Ditch (aka Jackson Ditch) 0300912 50.92 5,981 5,948 5,077 Cache la Poudre Ditch (aka Little Cache) 0300915 82.5 12,829 12,690 15,347 Taylor & Gill Ditch 03001029 12.17 2,944 2,959 2,856 New Mercer Ditch 0300913 85 6,473 6,596 6,509 Larimer County No. 2 Ditch 0300914 178.5 8,139 8,292 7,160 Fort Collins Irrigation Canal (aka Arthur 0300918 108.73 4,597 4,755 3,520 Ditch) Larimer & Weld Irrigation Canal 0300919 2797.47 75,834 76,300 74,188 Lake Canal 0300922 158.35 11,674 11,850 11,325 Coy Ditch 0300923 31.63 1,283 1,348 1,442 Boxelder Ditch 0300926 52.76 6,870 6,846 6,694 New Cache la Poudre Co. Ditch (aka 0300929 650 47,453 47,155 47,394 Greeley No. 2) Whitney Irrigation Ditch 0300930 61.18 11,293 11,452 11,779 BH Eaton Ditch 0300931 41.70 5,195 5,243 5,618 William R. Jones Ditch 0300932 15.52 3,572 3,513 3,420 Canal No. 3 (aka Greeley No. 3) 0300934 174.89 19,245 19,062 18,456 Boyd Freeman Ditch 0300935 54.05 941 994 870 Ogilvy Ditch 0300937 91.06 15,711 15,568 17,509 TOTAL ------405,075 407,219 399,103 1 Decreed amounts based on water rights records (sum of absolute rates) downloaded from CDSS HydroBase on 08/23/2007; physical capacities of canals may vary from the stated flow rates. 2 The period of record for the Munroe Canal is IY 1954-2009; the ditch was built as part of the C-BT Project.
For the 1950-2005 period common to all streamflows (Table 2) and diversions (Tables 6 and 7) discussed in this memorandum, the following observations based on the tabulated data are notable:
Average annual streamflows at the Canyon Gage = 227,693 AFY (from Table 2). Average annual irrigation diversions below the Canyon Gage (total shown in Table 7 minus upstream diversions by North Poudre Canal, Munroe Canal, and PVC) = 325,991 AFY, or 143 percent of flows measured at the Canyon Gage. Average annual irrigation diversions between the Canyon Gage and the Lincoln Street Gage (Pleasant Valley and Lake Canal [PVLC] through Coy Ditch) = 216,158 AFY, or 95 percent of flows measured at the Canyon Gage.
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If M&I diversions are added to the irrigation diversions between the Canyon Gage and Lincoln Street Gage, the average annual diversions = 229,472 AF, or 101 percent of flows measured at the Canyon Gage.
Table 2 shows that average annual streamflows at the Lincoln Street Gage are roughly 50 percent of the flows measured at the Canyon Gage. This appears to be inconsistent with the observations above showing diversions between the Canyon Gage and Lincoln Street Gage exceeding or nearly exceeding the flows measured at the Canyon Gage. There are two major factors that explain the observations: (1) the Hansen Supply Canal delivers C-BT water to the Poudre River below the Canyon Gage, averaging greater than 79,000 AFY, as described in Section 4.2; and (2) many ditches, particularly those in the lower Poudre Basin, rely on return flows from upstream uses— both irrigation return flows and M&I effluent discharges—in order to meet their demands.
In general, the vast majority of river flow in the basin originates from mountain snowmelt above the Canyon Gage and C-BT and other transmountain inflows, and therefore diversions greatly exceeding gaged flows and transmountain inflows are clearly indicative of the importance of return flows to the overall water supply in the Poudre Basin (and further downstream on the lower South Platte). This is not meant to imply that there are no inflows to the Poudre River below the Canyon Mouth, as spring/summer storm events and urban runoff certainly contribute to Poudre River flows, albeit on a generally infrequent basis. However, in a February 2009 interview with Water Commissioner George Varra, it was noted that when there are large rainstorms in the Poudre Basin on the plains downstream of the Canyon Gage, the increased flows tend to benefit lower South Platte users rather than increasing diversions to plains reservoirs in the Poudre Basin.
7.2 The "Big Four" Canals The North Poudre Canal (aka Livermore Canal, owned by NPIC); Larimer County Canal (owned by WSSC); Larimer Weld Irrigation Canal (owned by the Larimer and Weld Irrigation Company); and the New Cache la Poudre Company Ditch (aka Greeley No. 2, owned by the New Cache la Poudre Irrigation Company) are regarded as the "Big Four" ditches in the Poudre Basin (see Figure 16). Collectively, these four ditches account for 225,810 AFY, or about 55 percent of Poudre irrigation diversions each year on average based on IY 1950-2005 data in Table 7.
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Figure 16. Canals and Irrigated Lands Associated with the Big Four
Dist 3 Admin Tech Memo
dsAssociated with Big the Four Figure 16.Canals Irrigated and Lan
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The Munroe Gravity Canal (aka North Poudre Supply Canal) is also part of the NPIC system, and the Cache la Poudre Ditch (aka Little Cache Ditch) and the PVC are part of the Larimer and Weld Irrigation Company system. WSSC owns 26 percent of the Dry Creek Ditch (aka Jackson Ditch). If diversions for these ditches are added to the Big Four totals, the irrigation companies operating the Big Four account for more than 290,000 AFY, or 71 percent of agricultural diversions from the Poudre River for IY 1950-2005. Timnath Reservoir also serves the New Cache Company; diversions for the period of record IY 1973-2009 averaged greater than 11,000 AFY in addition to the agricultural diversions shown in Table 7. NPIC owns Fossil Creek Reservoir. Current practice is to divert much (if not all) of the Poudre River streamflow to Fossil Creek Reservoir and release any water not being stored in priority from the reservoir. The Water Commissioner uses this reservoir as an equalizer between the upper and lower portions of the Poudre Basin.
The Larimer and Weld Irrigation Company and the New Cache la Poudre Irrigation Company are proposed to interface with NISP operations through the delivery of South Platte River water stored in the NISP Galeton Reservoir to the Larimer Weld Canal and the New Cache Ditch in exchange for water diverted upstream at the PVC for delivery to NISP's Glade Reservoir.
Each of the Big Four canals is briefly summarized below based on information provided in the SPDSS Water District 3 memo, available here: Task 3 – Identify Key Diversion Structures, as well as the SPDSS memos for the respective ditch companies. Figure 16 maps the locations of the canals and the irrigated lands associated with each.
7.2.1 North Poudre Canal The North Poudre Canal (aka Livermore Canal) is owned by the NPIC and has a headgate diversion capacity on the North Fork of about 300 cfs. Shareholders in the NPIC generally receive 5.5 to 6 AF per share each year (there are 10,000 total shares), and about half of that yield is C-BT water (NPIC owns 40,000 C-BT units). Currently, about 70 percent of NPIC stock is owned by M&I water providers, including Fort Collins, Ault, Nunn, Eaton, Windsor, Severance, and the Tri- Districts. NPIC also owns 19 reservoirs, most of which are actively used for storage, exchange, and regulation throughout the ditch company's system.
LRE (2005e) describes the layout of the North Poudre Canal as follows:
The North Poudre Canal headgate is located on the north side of the North Fork Cache la Poudre River. The canal is carried through a tunnel for approximately one-mile before it is discharged into an open, earth-lined canal. The Livermore Lateral component of the North Poudre Canal delivers water to Park Creek Reservoir. Below Park Creek Reservoir, the canal splits into the No. 15 Bypass and the Buckeye Lateral. The Buckeye Lateral is the main extension of the canal. South of North Poudre Reservoir No. 15, the No. 15 Bypass intersects the Main North Poudre Supply Canal. The Buckeye Lateral continues east to the town of Buckeye, at which point it becomes the Boxelder Lateral. The Boxelder Lateral travels generally south from Buckeye to a point where it intersects the Main North Poudre Supply Canal [aka Munroe Gravity Canal].
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Fossil Creek Reservoir (Structure ID 0300927/0303774) is also owned by NPIC, but is located off of the mainstem of the Poudre River a few miles southeast of Fort Collins, far below NPIC's irrigation system. The use of Fossil Creek Reservoir to facilitate exchanges and unique operational aspects of the Fossil Creek Inlet are described in subsequent sections of this memorandum. Extensive details regarding the infrastructure, water rights, operations, and administrative aspects of the North Poudre Irrigation Canal are provided in the SPDSS NPIC memo, here: Task 5 – Key System, North Poudre Irrigation Company (LRE 2005d).
7.2.2 Larimer County Canal The Larimer County Canal is owned by WSSC. The headgate capacity of the Larimer County Canal is about 750 cfs. Approximately one-fourth of the ditch diversions are C-BT water, and the Larimer County Canal also diverts transbasin water delivered through the Grand River Ditch, Laramie-Poudre Tunnel, Cameron Pass Ditch, and Skyline Ditch. A number of reservoirs can be filled from the Larimer County Canal, including Curtis Reservoir, Rocky Ridge Reservoir, WSSC Reservoirs 3 and 4, Kluver Reservoir, and Black Hollow Reservoir. Several of these reservoirs cannot release stored water back into the Larimer County Canal, so the water is released to other ditches by exchange. Irrigation occurs all along the ditch, with about 50 percent occurring downstream (east) of Black Hollow Reservoir.
LRE (2005c) further describes the Larimer County Canal location as follows:
The headgate of the Larimer County Canal is located on the north side of the Cache la Poudre River, approximately 2 miles downstream of the mouth of the Poudre Canyon, 50 river miles downstream of the Laramie-Poudre Tunnel, 55 river miles downstream of Chambers Lake, and 63 river miles downstream of Long Draw Reservoir. The Larimer County Canal and its laterals convey water from the Cache la Poudre River approximately one mile south of Ted's Place to U.S. Highway 85 as far down as between Pierce and Ault in Weld County. Two major laterals extend from the Larimer County Canal: Pierce Lateral and Collins Lateral. Pierce Lateral extends east from Black Hollow Reservoir and Collins Lateral extends from the eastern extent of Larimer County Canal east of Highway 85.
Based on a 1990 report prepared in support of the City of Thornton's change of use case for WSSC shares, "the Larimer County Canal average annual diversions between 1950 and 1985 were 126.9 [AFY]/share without Jackson Ditch pro-rata entitlement and 129.6 [AFY]/share with the Jackson Ditch pro-rata entitlement" (LRE 2005c). Extensive details regarding the infrastructure, water rights, operations, and administrative aspects of the Larimer County Canal and the WSSC plains and mountains reservoir systems, are provided in the SPDSS WSSC memo, here: Task 5 – Key Structure, Water Supply and Storage Company.
The City of Thornton purchased just under 50 percent of the shares in WSSC in the mid-1980s (there are 600 total stock shares in the company), and diversions for irrigation continue as Thornton proceeds with its dry-up and revegetation of the lands historically irrigated with its
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acquired shares. Some of Thornton's consumptive use water on lands that have been revegetated is leased for augmentation credits and delivered down the Poudre to the South Platte.
7.2.3 Larimer Weld Irrigation Canal The Larimer Weld Irrigation Canal is owned by the Larimer and Weld Irrigation Company. It is used to fill Big Windsor Reservoir in the winter and spring, and the canal supplies irrigation water to more than 60,000 acres of land, generally situated between the WSSC system to the north and the New Cache Company system to the south (see Figure 16). At full supply, one share of Larimer and Weld Irrigation Company water is equal to 25 days of water at 1.44 cfs, or 72 AFY. The physical capacity of the canal is estimated to be about 1,000 cfs. Water diverted for storage in Big Windsor Reservoir cannot be released back to the Larimer Weld Irrigation Canal due to the reservoir's location on the downhill (south) side of the canal. As a result, a major inter-ditch exchange operation, described in Section 8 of this memorandum, is administered between the Larimer and Weld and New Cache Companies.
LRE (2005d) provides a more detailed description of the canal's layout: "The Larimer Weld Irrigation Canal is locally referred to as Eaton Ditch. The headgate for the canal is located on the north side of the Cache la Poudre River at the north side of the City of Fort Collins. The earth lined canal travels in a general easterly direction through Larimer County and continues into Weld County in Water District 1 [to a point approximately 5 miles west of the town of Cornish]."
The PVC and the Little Cache Ditch are also owned by affiliates of the Larimer and Weld Irrigation Company. Extensive details regarding the infrastructure, water rights, operations, and administrative aspects of the Larimer Weld Irrigation Canal and other canals and reservoirs associated with the Larimer and Weld Irrigation Company are provided in the SPDSS Larimer and Weld memo, here: Task 5 – Key Structure, Larimer and Weld Irrigation Company.
7.2.4 New Cache la Poudre Ditch The New Cache la Poudre Company Ditch, also known as the Greeley No. 2 Ditch, is owned by the New Cache la Poudre Irrigating Company (New Cache). There are eight affiliated irrigation and reservoir companies that are managed by New Cache, including the Cache la Poudre Reservoir Company. New Cache holds the largest senior water rights of the Big Four ditches, totaling 650 cfs. There are 2,500 shares of stock in New Cache; between 1950 and 2000, the yield of New Cache shares ranged from 4 to 28 AF per share, with an average of about 13 AF per share of direct flow water annually. Shareholders in the Cache la Poudre Reservoir Company (there are 3,000 total shares) receive additional water supplies from storage in Timnath Reservoir, and water is delivered to the New Cache Ditch from Big Windsor Reservoir by exchange.
LRE (2005f) describes the canal's geography as follows: "The headgate of the Greeley No. 2 Ditch…is located on the north side of the Cache la Poudre River approximately 2 miles southeast of the Town of Timnath. The earth-lined ditch diverts direct flow water from the Cache la Poudre River and conveys storage water released to the ditch through Timnath Reservoir Outlet Canal." The ditch travels in an easterly direction into Weld County, generally paralleling the Poudre
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River. In total, the New Cache Ditch is about 48 miles long, "consisting of three distinct ditch segments, 1) the main ditch for the first 24 miles, 2) the North Side Lateral for the next 12 miles, and 3) the North Side Extension for the last 12 miles" (LRE 2005f). The capacity of the New Cache Ditch is about 650 cfs.
Extensive details regarding the infrastructure, water rights, operations, and administrative aspects of the New Cache Ditch and other affiliated canals and reservoirs are provided in the SPDSS New Cache memo, here: Task 5 – Key Structure, New Cache la Poudre Irrigating Company and Cache la Poudre Reservoir Company.
7.3 South Side Ditches The PVLC is generally operated in conjunction with the "South Side Ditches" (New Mercer Ditch, Larimer County #2 Ditch, and Arthur Ditch), so called because they all divert from the south side of the Poudre River (see Figure 17). In aggregate, these four ditches have historically diverted more than 33,000 AFY (see Table 7). While not affiliated with any of the Big Four ditches described in the preceding sections, the PVLC and South Side Ditches are important to Poudre River administration because the City of Fort Collins is a major shareholder in all four. Presently, Fort Collins is using water from the PVLC and South Side Ditches for both potable and non- potable purposes; however, the water rights have been changed to allow potable municipal uses and for diversion by exchange at the Fort Collins pipeline diversions. These water rights will be significant in the context of the proposed Halligan Reservoir expansion undergoing NEPA review in the Poudre Basin, as they are also decreed for storage by exchange in Halligan.
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Figure 17. Canals and Irrigated Lands Associated with the "South Side Ditches"
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The SPDSS Water District 3 memo (LRE 2004a) describes some of the geographic and operational aspects of these ditches:
Pleasant Valley Lake Canal…is one of the "South Side" ditches (also include New Mercer, Larimer County #2, and Arthur Ditches). The majority owner of these ditches is the City of Fort Collins. They are used to irrigated parks and open space. PVLC also irrigates crops in the Bellvue area. PVLC delivers water for storage in Claymore Lake. When the canal is not in priority, water can be released from Claymore Lake…to the Poudre in exchange for diversion through the headgate. [Water stored in Claymore Lake is part of the supply that is delivered to shareholders of the Pleasant Valley & Lake Canal Company (PVLCC). Through an agreement between the City of Fort Collins and the PVLCC, Claymore Lake will continue to be used primarily for agricultural purposes, and the City of Fort Collins is entitled to use a larger proportion of the PVLCC's more junior water rights.] New Mercer Ditch…runs side by side with Larimer County Ditch #2 through the City of Fort Collins. The Mail Creek Ditch lands are also irrigated with New Mercer Ditch diversions. Larimer County Ditch #2…runs side by side with [New Mercer Ditch] through the City of Fort Collins. Larimer County Ditch #2 also delivers water to Warren Lake. Releases from Warren Lake irrigate Collindale Golf Course [owned by Fort Collins] and the grounds at the Hewlett Packard facility [located in the southeastern part of Fort Collins, near to the Fossil Creek Reservoir inlet]. Fort Collins Irrigation Canal aka Arthur Ditch…is the ditch that goes through the Colorado State University campus.
The SPDSS Fort Collins memo (LRE 2005b) elaborates on the city's ownership and use of these facilities:
The City is a major shareholder in several of the irrigation companies that historically irrigated lands on the south side of the Cache la Poudre River in the vicinity of Fort Collins. The City owns shares in the Arthur, New Mercer, Larimer County No. 2 Ditch, Warren Lake and the Pleasant Valley and Lake Canal companies, and is sole owner in the Chaffee Ditch. The City uses part of its share water in these ditches for non-potable irrigation of golf courses, parks and other public areas in the vicinity of the ditches as they wind through the City. The City also changed its ownership in these ditches…to be able to divert its share water for potable uses or into storage.
The changes in use of PVLC and South Side Ditches water rights are further described as follows:
The City has changed its ownership in the South Side ditches and other irrigation water rights in water court…The City's ownership in these water rights has generally been adjudicated as alternate points to one another, the Fort Collins Pipeline, and to the PVP via the North Poudre
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Supply Canal. Therefore, these water rights are used to satisfy non-potable demands and for potable uses.
The SPDSS Fort Collins memo, available here Task 5 – Key Municipal User, City of Fort Collins, provides additional details regarding the City of Fort Collins's pro-rata share ownership in the PVLC and South Side Ditches as well as diversion limitations associated with the decreed water rights changes. Section 8 – Water Exchanges in the Poudre Basin Water exchanges play a significant role in the operation and administration of water use in the Poudre Basin. These exchanges evolved as a means to improve the efficiency of beneficial water use as well as to allow ditch companies to make use of water supplies that they own, but that were physically inaccessible to the irrigators under those ditches.
8.1 Overview of Water Exchanges in the Poudre Basin Wilkins-Wells et al. (2002) provide a valuable look at the history and future of water exchanges in the Poudre River Basin, including the following explanation of why exchanges occur:
Why do exchanges occur? They occur primarily because water supply entities, in attempting to maximize the beneficial use of their river or storage decree, often must overcome geographical constraints affecting their water supply, address temporary water shortages, minimize river or canal transit losses, improve the timing of water releases from storage, address local water quality issues, or better regulate irrigation canal flows.
For instance, low river flows can prompt a junior decree holder to request borrowing the use of a senior decree diversion, then subsequently repaying the senior decree holder an equal amount of water diverted at another geographical point or time. It is frequently not immediately apparent to an observer how such an exchange benefits a senior decree holder. However, closer inspection often reveals significant improvements in the timing and quality of water to the senior decree.
For example, Big Windsor reservoir is filled through the Larimer Weld Irrigation Canal, but due to its location on the south (downhill) side of the canal, it cannot release water back to Larimer and Weld irrigators. Instead, the Larimer and Weld Company releases water to the New Cache Ditch further downstream and, in exchange, diverts at the upstream Larimer and Weld headgate using New Cache's water rights priority.
Similarly, the WSSC system is used to fill several reservoirs that cannot release back to the Larimer County Canal, so this water is released to the downstream Larimer and Weld system. The NPIC owns 40,000 units in the C-BT Project, but the North Poudre Canal on the North Fork of the Poudre River and the Munroe Gravity Canal on the mainstem of the Poudre River are located far above the Hansen Supply Canal release point to the Poudre River mainstem for the delivery of
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C-BT water. Through multiple exchanges, NPIC diverts water from the North Fork and mainstem of the Poudre River and releases a like amount of C-BT water to downstream users.
These exchanges represent just a few of the many that may occur in the Poudre Basin, as explained by Wilkins-Wells et al. (2002):
There are numerous instances of exchanges in the Cache La Poudre Basin. The practice evolved so dramatically in a relatively short time just prior to 1900 that a future Water Commissioner was compelled to develop a working table of some 1,243 potential exchanges he might be called upon to oversee. These exchanges were formally adjudicated in 1976. Although there are 1,243 adjudicated river exchanges in the Cache La Poudre Basin today, only 11 account for the majority of water exchanged. Certain years may see activity in some of the 1,232 other exchanges, but nowhere to the degree exhibited by the eleven principal exchanges. These 11 exchanges together averaged about 46,000 [AF] of water annually over a 25-year period (1973-2001), or more than 95 percent of all exchange activity occurring in the basin. A rough indicator of the importance of these exchanges to river basin management is that 46,000 [AF] amounts to approximately 17 percent of the average total annual flow of the river.
Wilkins-Wells et al. (2002) also emphasize that the functionality of many of the largest exchange operations has been greatly enhanced since the start up of the C-BT Project in the early-1950s:
Although several of the 11 principal exchanges precede in time the coming of transbasin water supplied by the NCWCD through the [C-BT] Project, the economic value of these exchanges to their participants has increased as a result of the project. The exchanges have been, for the most part, easier to perform since C-BT project water was first made available in 1953. Over the years, the amount of water actually exchanged between entities in the Cache La Poudre Basin appears to have been dependent upon the quota of water announced by the conservancy district for its water users. High quota years generally see more exchange activity than low quota years. Thus, many of the exchanges may be said to be "quota dependent."
As noted in Section 4.2, since the C-BT Project began, there has been a steady transfer of units from agricultural use to M&I use. After noting the significant role C-BT water plays in many of the Poudre Basin's largest exchanges, Wilkins-Wells et al. (2002) observe that, "Many farmers today speculate that once the C-BT water has been transferred completely out of agriculture, many of the current principal exchanges will decline in importance or become inactive." Moreover, some irrigators expressed fears that continued transfers out of agriculture "may force irrigators to adopt cropping systems to a water regime characterizing the Cache La Poudre Basin prior to the C-BT project itself." However, it should be noted that continued transfers of water out of agriculture will result in the permanent dry-up of formerly irrigated lands and less overall demand for irrigation water. With less demand, there may be less need for inter-ditch exchanges,
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if not in the total number of exchanges, perhaps in the volume of water that must be exchanged throughout the Poudre Basin.
Fossil Creek Reservoir, owned by NPIC, is also particularly important to Poudre Basin exchange operations, as described by Wilkins-Wells et al. (2002):
The building of Fossil Creek Reservoir by the [NPIC], and some 40 miles below its main North Poudre Canal headgate, greatly facilitated the expansion of water exchanges throughout the basin…In effect, it was an early "water bank" for the basin. Fossil Creek Reservoir had an ideal location, situated immediately upstream of the headgates of many senior ditch company trading partners in the lower portion of the basin. These included Greeley #2 Canal, Whitney Ditch, Ogilvy Ditch, and several smaller ditches just west of Greeley, Colorado. In later years, Fossil Creek Reservoir became a central pooling place for [C-BT] units of water owned by many canal companies and individuals throughout the basin. Fossil Creek Reservoir virtually acted as a water bank for several canal companies and individuals. In addition, it captures and stores much of the City of Fort Collins storm drainage water. Today, Fossil Creek Reservoir is highly coveted by county and municipal government for its recreational and open space value. Throughout the basin, urbanization is gradually placing more pressure on the use of such facilities for exchanges, particularly boating and other recreational uses that desire more constant water storage levels, although reservoir owners have no legal obligation to accommodate recreational needs.
8.2 Major Exchanges Represented in EIS Modeling Carney and Baldo (2005b) identified the major exchanges represented in the hydrologic models originally developed for the NISP and HSWSPs EISs in the mid-2000s; these are listed below, with edited descriptions from the source document (see also Section 2.2.1 of CTP Model Review Report [CDM 2011] for more recent simplifications of exchanges dependent upon C-BT water). Bracketed text indicates changes that were made to the modeling of the exchanges during the CTP process due to the development of the C-BT Projection Tool or other information. Upon comparison of documentation, these modeled exchanges appear to be, for the most part, consistent with the 11 major exchanges reported on by Wilkins-Wells et al. (2002).
1. Worster Reservoir to NPIC. Worster Reservoir is owned by Divide Canal and Reservoir Company and is used by Larimer and Weld. Larimer and Weld releases from Worster to supply NPIC. In exchange, NPIC releases C-BT water that is diverted at the PVC or the Larimer Weld Irrigation Canal. [The NPIC releases are not explicitly modeled in the CTP. Some exchanges to the Larimer and Weld system via plains reservoirs are assumed to be settled in cash.] 2. NPIC out of priority diversions exchanged for C-BT water. NPIC will frequently provide water to its users by diverting out of priority at its headgates and releasing a like amount from either their Fossil Creek Reservoir or C-BT supplies to satisfy downstream calls for water.
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3. Greeley Mountain Reservoir storage to NPIC (diverted at Munroe Canal). The City of Greeley owns multiple mountain reservoirs (Milton Seaman Reservoir, Comanche Reservoir, Hourglass Reservoir, Twin Lake Reservoir, and Peterson Lake) from which it will release to supply NPIC demands in exchange for C-BT water. [This exchange is accounted for in the C-BT Projection Tool.] 4. NPIC Fossil Creek Reservoir Exchanges. Fossil Creek Reservoir is owned by NPIC and is used by the water commissioners for multiple purposes by multiple users (see Section 9.2). Its operation varies widely between months and years. The major trades and ownerships within the reservoir were represented in the MODSIM network, including one specific exchange between NPIC and New Cache. New Cache trades C-BT water they own for releases from Fossil Creek Reservoir to satisfy their demands. This is a more efficient use of water as it reduces transit losses that would occur if the C-BT water was delivered directly to New Cache. [The New Cache C-BT exchange is accounted for in the C-BT Projection Tool.] 5. Larimer Weld and New Cache Direct Decree Exchange. When the peak runoff is subsiding and the Larimer and Weld rights are about to be called out, Larimer and Weld will release Big Windsor Reservoir water to New Cache in exchange for diversion rights under Priority #37. [Note that the CTP does not directly account for Big Windsor Reservoir releases to match Priority #37 diversions.] 6. Larimer Weld and New Cache C-BT exchange. Larimer and Weld will release Big Windsor water to New Cache in exchange for C-BT water. [This exchange is accounted for in the C-BT Projection Tool.] 7. Larimer Weld and WSSC Exchanges. Due to the location of Long Pond, Kluver, and Reservoir No. 4, WSSC cannot directly utilize their storage water. Therefore, WSSC releases water to the Larimer and Weld Canal and in return is allowed to draw upon Larimer-Weld storage reservoirs: Reservoir No. 8, Annex 8, and Cobb Lake. [The CTP does not include direct accounting to make sure the exchange volumes are equal. Any difference is assumed to be settled in cash.] 8. Joe Wright Reservoir Releases to NPIC. The City of Fort Collins will regularly deliver water stored in Joe Wright Reservoir to NPIC. In exchange, NPIC will trade C-BT water to Fort Collins. 9. PVLC – Claymore Reservoir Exchanges. PVLC will divert water out of priority at its headgate on the river to supply its users, and in exchange will release an equal amount from Claymore Lake to the river. 10. Three-Way Agreement. Also known as the Reuse Plan, the City of Fort Collins, WSSC, and Platte River Power Authority have an agreement for a series of exchanges to efficiently utilize available water resources. 11. Chambers Lake Fulfillment of JOP Requirements. Under the JOP, the mountain reservoirs will release a constant flow (10 cfs) during the winter. Barnes Meadow Reservoir, owned
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by Greeley, supplies the required flows between November and March of each year, except when the reservoir levels in Barnes Meadow reach a critical point, triggering WSSC to satisfy the minimum streamflow requirements by releasing from Chambers Reservoir. The City of Greeley credits WSSC with C-BT water for any JOP releases fulfilled by WSSC.
Each of these exchanges plays a role in improving the efficiency of water allocation in the Poudre Basin. However, in order for the exchanges to work properly, each requires administration and detailed bookkeeping by the Water Commissioner to ensure that the involved entities are able to divert the amounts of water to which they are entitled. Section 9 – Other Key Administrative Issues To this point, this memorandum has discussed many varied topics related to the administration of water in the Poudre Basin, including historical gaged streamflows, transbasin imports (including the C-BT Project), mountain reservoir systems, major irrigation and M&I water suppliers, and the exchange operations that improve the efficiency of water allocation in the basin. The following sections focus on a few additional facets of river administration that are currently important to certain reaches of the Poudre River on the plains (river dry-up points and Fossil Creek inlet operations), or may become more significant in the future (fish hatchery and recreational minimum flow decrees).
9.1 River Dry-up Points Another unique aspect of Poudre Basin water administration is related to practices for filling reservoirs, as described by Wilkins-Wells et al. (2002):
In the 1930s, one of the former Water Commissioners contributed yet another innovation in the basin. This involved obtaining agreement from water users and water supply entities to fill basin reservoirs beginning at the highest elevation first, then gradually moving down the basin to fill reservoirs at lower elevations. This contributed to the benefit of all water users in the basin by ensuring that storage flows were secured as high in the basin and as early as possible in the water year. This policy served everyone, including the many exchange partners that depended upon these reservoirs to complete their exchanges.
This approach to reservoir filling continues today and is exemplified by the upstream-to- downstream sequential filling of Terry Lake, Big Windsor Reservoir, and Timnath Reservoir. During the winter, Timnath Reservoir has the #1 priority storage right on the Poudre River (LRE 2004a). However, Terry Lake and then Big Windsor Reservoir are often allowed to divert out of priority—and to take all the available water in the river at the point of diversion—to fill before Timnath Reservoir. As explained below, this operation sometimes leads to river dry-up points that are administered by the Water Commissioner.
In practice, the occurrence of a dry-up point means that a particular diversion structure (i.e., headgate or pipeline intake) diverts the entire flow of the Poudre River to satisfy the owner's
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water rights. The diversions that result in the dry-up points may be for either direct use or for reservoir storage. Dry-up points occur at different locations during the non-irrigation (winter) and irrigation (summer) seasons. These locations are described below (and listed in upstream-to- downstream order) based on interviews with Water District 3 Water Commissioner George Varra in December 2005, February 2009, and June 2010. The dry-up points are also illustrated in the Water District 3 straight-line diagram, as well as in Figure 18 below.
Non-irrigation season (winter) dry-up points: — Below the Greeley Filters Pipeline intake, occasional dry-up duration of 1 to 2 days in the winter. — Below the Little Cache Ditch/Terry Lake inlet, November to mid-December. The dry- up reach continues through Laporte. Once Terry Lake fills, water flows past this diversion point to the Larimer Weld Irrigation Canal. — Below the Larimer and Weld Irrigation Canal, November through March. Larimer and Weld diverts about 8 cfs of return flows below the Little Cache Ditch when there is dry-up below Little Cache. The diverted water is stored in Big Windsor Reservoir, which is junior to Timnath Reservoir, but is allowed to divert out-of-priority during the winter under a handshake agreement. Once the upstream Little Cache diversion to Terry Lake ceases in mid-December, the diversions at Larimer and Weld increase to about 14 to 18 cfs. Although dry-up occurs directly below the headgate, approximately 3 to 4 cfs of return flows accrue to the Poudre River above the Lincoln Street Gage, approximately 3 miles downstream. — Below the Timnath Reservoir inlet, November through March. The Timnath inlet diverts about 15 cfs, including return flows accruing to the Poudre River below the Larimer and Weld headgate as well as effluent from Fort Collins Wastewater Treatment Facility (WWTF) No. 1 (aka Mulberry WWTF).
— Below the Fossil Creek Reservoir inlet, November through March. This diversion structure is normally set so that the first 150 cfs in the river at this location are diverted into the Fossil Creek inlet. There is some leakage at this diversion structure, so even though the headgate is set to divert the entire flow, a small amount of water leaks past the diversion dam back to the river.
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Figure 18. Poudre River Dry-up Points
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Irrigation season (summer) dry-up points: — Watson Lake Fish Hatchery, operated by the Colorado Division of Wildlife, is allowed to divert the whole flow of the river and return the whole flow of the river below the hatchery; there are no intervening water rights between the intake and return. The dry-up section is between ¼- and ½-mile long and occurs only when there are very low flows (e.g., 2002 flows, August/September of extreme dry years). The return point is just upstream of the Jackson Ditch headgate. — Late-season (i.e., August, September) below the Larimer and Weld Irrigation Canal. — Below the Fossil Creek Reservoir inlet during very low flow except during rain events. As noted previously, the first 150 cfs of streamflow in the Poudre River at this location is normally diverted into the Fossil Creek inlet canal, but a small amount of water typically leaks past the diversion dam. — Below the Greeley #3 Ditch, occasional dry-ups lasting a few days, except for downstream augmentation replacements. — Below Ogilvy Ditch, the last diverting ditch before the confluence with the South Platte River, occasional dry-ups lasting a few days. — The historical general administration goal was to deliver no water to the South Platte River unless there was a call. New augmentation plans will likely require that some water be delivered downstream of the ditch to replace South Platte River depletions.
As stated above, the Watson Lake Fish Hatchery dry-up reach can extend from ¼- to ½-mile below the diversion point. In general, return flows begin accruing to the river shortly below a dry-up point. These return flows may be from subsurface sources (e.g., irrigation seepage losses or residential septic system effluent) or surface returns (e.g., irrigation tailwater returns, M&I wastewater treatment plant effluent discharges, or tributary inflows). The overall importance of return flows to the Poudre River system was previously discussed in Section 3 and Section 7. There may also be headgate leakage that contributes flow immediately downstream of an administered dry-up point.
9.2 Fossil Creek Reservoir Inlet Operations As described in Section 8, Fossil Creek Reservoir is owned by NPIC and plays an important role in several of the Poudre Basin's major water exchanges. In addition, Fossil Creek Reservoir intercepts effluent discharges from Fort Collins WWTF No. 2 (aka Drake WWTF) as well as urban storm drainage runoff. Fossil Creek Reservoir is filled through a long inlet ditch that diverts from the Poudre River below the Timnath Reservoir inlet and Boxelder Ditch headgates, but above the Fort Collins Nature Center (aka Environmental Learning Center) and the Boxelder Gage described in Section 3. The inlet diversion has some unique operational characteristics that affect river administration, as described below:
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SPDSS Water District 3 memo – Fossil Creek Reservoir Inlet Canal gates are always open. Up to 150 cfs from the Poudre River is routed through Fossil Creek Reservoir, which generally operates as an equalizing reservoir. When Poudre River flows are less than 150 cfs, the feeder canal essentially is the river. [Typically, for flows below 150 cfs, approximately 10 to 25 percent leak past the diversion structure into the Poudre River downstream.] SPDSS NPIC memo – The Water Commissioner for Water District 3 is responsible for diversions through and releases from Fossil Creek Reservoir. Water stored in Fossil Creek Reservoir for the purpose of equalization and administration of the Water District is considered river water and NPIC is not entitled to the use of that water. SPDSS Fort Collins memo – Drake Water Reclamation Facility (DWRF) currently has an operating capacity of 27.3 mgd and currently discharges an average of about 14 mgd into either the Fossil Creek Reservoir inlet ditch or the Cache la Poudre River. [Note, however, that field observation found the outlet gate for discharge directly to the Poudre River buried in sediment. This evidence indicates that the DWRF never discharges to the Poudre River.] The effluent stream from DWRF is [almost always] conveyed through Fossil Creek Reservoir and through the Fossil Creek outlet ditch to the Cache la Poudre River near the Larimer County/Weld County border [approximately 5.4 river miles downstream of the point at which the DWRF could discharge directly to the Poudre River].
9.3 Fish Hatchery and Recreational Minimum Flows Much of the Poudre River mainstem, headwaters streams, and tributaries (including the South Fork) above Poudre Park have been designated as part of the National Wild and Scenic Rivers System. This system was created by Congress in 1968 "to preserve certain rivers with outstanding natural, cultural, and recreational values in a free-flowing condition for the enjoyment of present and future generations" (http://www.rivers.gov). The Poudre River, which traverses mostly USFS lands in the Wild & Scenic reaches, is the only river to receive this designation in the State of Colorado.
In 1973, the Colorado General Assembly enacted Senate Bill 97, which created the Colorado Instream Flow (ISF) Program. This program granted exclusive authority to the CWCB to appropriate water rights for the purpose of maintaining minimum flows between specific points on a river, i.e., through a river reach. As stated on the CWCB's ISF Program website, "These rights are administered within the state's water right priority system to preserve or improve the natural environment to a reasonable degree." Examples of environments protected through the ISF Program include:
Coldwater and warm water fisheries Waterfowl habitat
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Riparian vegetation, unique hydrologic and geologic features Critical habitat for threatened or endangered native fish.
A review of the CWCB's ISF database indicates that there are 57 decreed ISF water rights within the Poudre River Basin (Water District 3), all located upstream of the confluence of the Poudre River mainstem and the North Fork. The decreed minimum flow rates vary from reach-to-reach, and may also vary by time of year. In many cases, these decreed ISF reaches coincide with the reaches designated as Wild & Scenic.
As noted, there are significant areas of the Poudre River Basin that have been protected in the interest of preserving the environment to a reasonable degree. None of these protected reaches would be directly impacted by the proposed projects (NISP and HSWSPs) currently undergoing NEPA review. However, there are three water rights decreed for fish hatchery and recreational purposes below the Canyon Mouth that are junior to most water rights in the basin, but are senior to several of the contemplated exchanges for NISP and HSWSPs. Specific to NISP, the fish hatchery and recreational flow decrees are junior to the Grey Mountain storage right (priority date May 2, 1980). Although these three water rights are junior, NCWCD agreed to curtail NISP diversions under the Grey Mountain storage right to the extent curtailment of the NISP diversions would meet the minimum flow criteria at these downstream points.
The fish hatchery and recreational water rights are decreed for the Watson Lake Fish Hatchery, the Fort Collins boat chute, and the Fort Collins Nature Center (see Figure 19). The recreational minimum flows are not part of the CWCB's ISF Program, but were decreed for instream beneficial use prior to the 2001 legislation (Senate Bill 01-216) authorizing Recreational In-Channel Diversions. At the fish hatchery, water is diverted from the river and routed through the hatchery and returned to the river upstream of other users. The reach between the intake and outlet of the fish hatchery can be dried up by the diversion into the hatchery (see Section 9.1).
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Figure 19. Poudre River Fish Hatchery and Recreational Minimum Flow Points
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19.Poudre RiverFish Hatchery and Recreational Minimum Flow Points
Figure
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During the ongoing NEPA processes, the associated water rights decrees and NCWCD's stipulations were made available from the DWR and NCWCD, facilitating a better understanding of the fish hatchery and recreational flow rates that should be simulated in the CTP. Details from the decrees are as follows:
Watson Lake Fish Hatchery (Case No. 85CW201; Admin No. 49308.41098) — 50 cfs summer (April 15-October 14) — 25 cfs winter (October 15-April 14). Fort Collins boat chute (Case Nos. 86CW371 and 2000CW236; Admin No. 50038.00000) — 30 cfs (May 1-August 31) — 5 cfs (September 1-April 30). Fort Collins Nature Center (Case Nos. 86CW371 and 2000CW236; Admin No. 49722.00000) — 30 cfs (May 1-August 31) — 5 cfs, with all river flows between 5 cfs and 25 cfs to be shared equally between Fort Collins and the City of Thornton, and Fort Collins is entitled to no more than 15 cfs (September 1-April 30).
Although the Nature Center recreational water right was not made absolute until Case No. 2000CW236, at the flow rates specified above, NCWCD and Fort Collins have an Amended Stipulation (Consolidated Case Nos. 85CW206, 85CW207, 85CW208, 85CW209, 85CW210, and 89CW122) that is dated June 1992 and assumed by both parties to supersede the language in the decrees governing operations as it affects the water rights of NCWCD and Fort Collins. Specifically, the Amended Stipulation calls for flow rates of 50 cfs (April 15-October 14) and 25 cfs (October 15-April 14) at the Nature Center diversion dam.
Note that while NCWCD is subject to the flow criteria in the stipulation, other water users with decrees more junior than the fish hatchery and recreational flows decrees are only required to curtail diversions to meet the flow targets specified in the decree in Case No. 2000CW236. In terms of the administration of these water rights, the Nature Center recreational water right has never placed a call on the Poudre River. According to Fort Collins, there has never been a time when a junior water right was diverting when the Nature Center right was not satisfied. Additional information regarding the fish hatchery and recreational flow decrees can be found in the CTP Model Review Report (CDM 2011).
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Section 10 – References Camp Dresser & McKee Inc. (CDM). 2011. NISP/HSWSPs Common Technical Platform Model Review Report.
Carney, Shaun, and Marc Baldo. 2005a. NISP Technical Memorandum No. 4 Colorado-Big Thompson Operation in the Poudre River MODSIM Network.
Carney, Shaun, and Marc Baldo. 2005b. NISP Technical Memorandum No. 3 Network Exchanges.
Colorado Division of Water Resources (DWR). 2006. A Summary of Compacts and Litigation Governing Colorado's Use of Interstate Streams.
Colorado Division of Water Resources. 2010a. Synopsis of Colorado Water Law. Revised Edition, November.
Colorado Division of Water Resources. 2010b. Water Rights Tabulation, Water Division 1. July.
Colorado Division of Water Resources. 2011. Prior Appropriation Law, website: http://water.state.co.us/SurfaceWater/SWRights/Pages/PriorApprop.aspx. Accessed February 25, 2011.
Colorado Foundation for Water Education (CFWE). 2009. Citizen's Guide to Colorado Water Law. 3rd Edition.
Colorado Water Conservation Board (CWCB). 2004. Statewide Water Supply Initiative. Final Report, Section 4 – Legal Framework for Water Use. Prepared by Camp Dresser and McKee Inc.
Colorado Water Conservation Board. 2011. Statewide Water Supply Initiative 2010. Final Report, Appendix B – Overview of Colorado Water Law. Prepared by Camp Dresser and McKee Inc.
DiNatale, Kelly. 2008. Water Law and Allocation in the SW. Lakeline, Winter 2008, pp. 29-33.
Gibbens, Jerry. 2006 (revised). NISP (Phase II) Technical Memorandum NO. 6C: South Platte River Hydrology.
Laflin, Rose. 2005. Irrigation, Settlement, and Change on the Cache la Poudre River. Special Report Number 15. Colorado Water Resources Research Institute, Colorado State University.
Leak, Alan J. (instructor). 2010. Water Rights Engineering. Presented by Urban Watersheds Research Institute.
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Leonard Rice Engineers (LRE). 2004a. SPDSS Memorandum, Task 3 – Identify Key Diversion Structures, Notes from Water District 3 Meeting." Final, June 9 (Revised August 2007).
Leonard Rice Engineers. 2004b. SPDSS Memorandum, Task 5 – Key Structure, Grand River Ditch. Final, April 6.
Leonard Rice Engineers. 2004c. SPDSS Memorandum, Task 5 – Key Structure, Laramie Poudre Tunnel. Final, April 6.
Leonard Rice Engineers. 2004d. SPDSS Memorandum, Task 5 – Key Structure, Skyline Ditch. Final, April 6.
Leonard Rice Engineers. 2004e. SPDSS Memorandum, Task 5 – Key Structure, Wilson Supply Ditch. Final, April 6.
Leonard Rice Engineers. 2004f. SPDSS Memorandum, Task 5 – Key Structure, Cameron Pass Ditch. Final, April 6.
Leonard Rice Engineers. 2004g. SPDSS Memorandum, Task 5 – Key Structure, Michigan Ditch. Final, April 6.
Leonard Rice Engineers. 2005a. SPDSS Memorandum, Task 5 – Key Structure, Bob Creek Ditch. Final, July 15.
Leonard Rice Engineers. 2005b. SPDSS Memorandum, Task 5 – Key Municipal User, City of Fort Collins. Final, January 5.
Leonard Rice Engineers. 2005c. SPDSS Memorandum, Task 5 – Key Structure, Water Supply and Storage Company. Final, March 5.
Leonard Rice Engineers. 2005d. SPDSS Memorandum, Task 5 – Key Structure, Larimer and Weld Irrigation Company. Final, March 5.
Leonard Rice Engineers. 2005e. SPDSS Memorandum, Task 5 – Key System, North Poudre Irrigation Company. Final, March 5.
Leonard Rice Engineers. 2005f. SPDSS Memorandum, Task 5 – Key Structure, New Cache la Poudre Irrigating Company and Cache la Poudre Reservoir Company. Final, March 5.
Leonard Rice Engineers. 2006a. SPDSS Memorandum, Task 5 – Key Structure, Northern Colorado Water Conservancy District and Colorado-Big Thompson Project. Final, July 7 (Revised).
Leonard Rice Engineers. 2006b. SPDSS Memorandum, Task 5 – Key Municipal User, City of Greeley. Final, March 31.
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MWH. 2004. NISP Phase II Alternative Evaluation. Final Report.
Pineda, Andy. 2005. Memorandum: C-BT Operations, Dry Year Yields Summary, and Firm Yield Assessment.
Pineda, Andy. 2009. Memorandum: Projection Tool Development for C-BT Project Operations for the NISP-HSWSP Common Technical Platform Hydrologic Analysis. Northern Water, September 22.
Riverside Technology, Inc. (RTi). 2005a. Cache la Poudre Network Model – A Comprehensive Description of Data Development and Model Operations for the Baseline Scenario. Prepared for Fort Collins Utilities and City of Greeley Water and Sewer Department. Provisional Report, January 2005.
Riverside Technology, Inc. (RTi). 2005b. Addendum to Cache la Poudre Network Model – A Comprehensive Description of Data Development and Model Operations for the Baseline Scenario. Prepared for Fort Collins Utilities and City of Greeley Water and Sewer Department. October 2005.
Wilkins-Wells, John, David M. Freeman, Annie Epperson, Shawn Hoff, Raymond L. Anderson, and Andrew Griguhn. 2002. Water Exchanges and Agricultural Production in Northeast Colorado: Opportunities and Constraints for the Future. Colorado State University Agricultural Experiment Station Research Project. July 10.
Wolfe, Dick. 2005. Surface Water and Ground Water Administration in Colorado – "Water 101.5."
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