Final Draft Technical Report McDonnell Creek Diversion Dam ... · Final Draft – December 2004...

Final Draft Technical Report

McDonnell Creek Diversion Dam

Prepared For Inclusion In Dungeness River Agricultural Water Users Association Comprehensive

Irrigation District Management Plan

December 2004

Prepared by:

Final Draft – December 2004

McDonnell Creek Page i

Table of Contents 1.0 Introduction......................................................................................................................... 1 2.0 Alternatives Reviewed ........................................................................................................ 1

2.1 Alternative 1 - Do-nothing.............................................................................................. 1 2.2 Alternative 2 - Rehabilitate Diversion Dam for Fish Passage ........................................ 1 2.3 Alternative 3 - Rehabilitate Irrigation System and Remove Diversion .......................... 2

3.0 Effects of Each Alternative................................................................................................. 2 3.1 Hydrology ....................................................................................................................... 2 3.2 Fisheries .......................................................................................................................... 5 3.3 Regulatory....................................................................................................................... 6

4.0 Costs.................................................................................................................................... 7 4.1 Alternative 1.................................................................................................................... 7 4.2 Alternative 2.................................................................................................................... 7 4.3 Alternative 3.................................................................................................................... 7

Figures Figure 1 - McDonnell Creek Diversion Improvements Figure 2 - Generic Rock Ramp Figure 3 - McDonnell Creek Diversion Improvements Alternatives 3A and 3B Comparison

Appendix Appendix A Memo from Byron Rot, JKT


McDonnell Creek Page 1

1.0 Introduction

The purpose of this technical report is to compare alternatives for the Agnew Irrigation District (AID) diversion from McDonnell Creek. Concerns have been expressed by the Jamestown S’Klallam Tribe (JKT) as to the use of McDonnell Creek as a conveyance for water discharged from the AID’s main canal and to the impacts from the dam, fish ladder and fish bypass systems. The two main habitat issues are potential for flow augmentation in attracting Dungeness River fish to McDonnell Creek and the effects the current dam and its operation has on juvenile fish passage. A desire has been expressed by JKT to repair or remove the dam and to modify the operations of the AID main canal to reduce or eliminate the discharge into the creek. A copy of a memo from Byron Rot of JKT is appended to this report for reference. 2.0 Alternatives Reviewed

Three alternatives were reviewed; the do-nothing alternative which keeps the current operation; an alternative which rehabilitates the current diversion dam to improve fish passage and an alternative which modifies the irrigation water delivery system to reduce discharges to McDonnell Creek. Figure 1 illustrates the alternatives. A description of each follows.

2.1 Alternative 1 - Do-nothing The do-nothing alternative will preserve the existing dam and operations of AID. Small improvements to the configuration of the fish ladder and fish bypass system can be performed to improve approach conditions to the fish ladder and the outlet of the fish bypass pipe, the costs of which are small. The improvements may result in improved downstream and upstream fish passage and survival. An issue discussed by JKT is the blockage of the existing fish ladder (a Denil fish ladder) during low flows to provide sufficient water for operation of the fish screen and fish bypass system. That operation provides for downstream passage of juveniles but not upstream passage during low flow periods. The operation of the dam at low flows would not change as sufficient flow in the creek is not available to operate the fish bypass system and the fish ladder.

2.2 Alternative 2 - Rehabilitate Diversion Dam for Fish Passage Alternative 2 includes the rehabilitation of the current diversion for better fish passage. The alternative reviewed is construction of a full-width rock ramp fishway. This fishway would consist of rock fill placed downstream of the dam that slopes down to the base of the stream channel. The purpose of a rock ramp fishway is to provide a hydraulically rough channel similar to rapids that allow fish to swim upstream at all flow levels. It would be designed for passage of all life stages. Rock ramp fishways have been constructed successfully with slopes exceeding 5%, however agencies in the Pacific Northwest have required slopes maximum slopes of 5% to be conservative. Figure 2 presents a generic design of a rock ramp fishway. The dam would operate in a similar manner as it currently does with diversions into the canal located on the right bank. Low flow operations may be similar to existing conditions unless less flow is discharged from the fish bypass system allowing flow to be discharged down the new rock ramp fishway. In addition to the fishway, improvements to the creek channel from the fishway through the SR101 right-of-way could be performed to create a more natural channel to improve habitat and passage.



2.3 Alternative 3 - Rehabilitate Irrigation System and Remove Diversion Alternative 3 includes improving Agnew Irrigation District facilities so that irrigation flow bypasses the reach of McDonnell Creek currently used for conveyance. In addition, the existing diversion dam would be partially or fully removed. Even with this alternative, the spillway from Agnew Canal to McDonnell Creek would still operate to spill overflow from the canal when needed. Specific components of this alternative are:

1. Construct a new control structure at the Agnew main canal. 2. Increase the capacity of the existing open channel lateral/ditch from the Agnew Canal to

Atterberry Rd and along Sherburne Rd. 3. Provide a spillway to a tributary of Matriotti Creek. 4. Replace the lower section of lateral/ditch from Sherburne Rd to the existing Agnew

facilities adjacent to McDonnell Creek with a new pipeline. 5. Remove or partially remove the existing dam on McDonnell Creek and restore that

section of creek to allow for better fish passage.

For the removal of the existing dam on McDonnell Creek we assumed the dam would be cut down about four feet, the sediment deposited upstream of the dam would be removed and the channel restored, a series of rock weirs constructed from the existing dam downstream to step the channel down and the weirs backfilled with the gravel material excavated from upstream of the dam to create a more natural channel through the weirs. The canal infrastructure located on the right bank would be removed and the banks stabilized. Options A and B of Alternative 3 represent two routes of the proposed pipeline to deliver water to the McDonnell Creek Diversion (see Figure 3). Both routes accomplish the same goal. Alternative 3A follows the generally the same route as the existing lateral. Alternative 3B is slightly shorter, but has a slightly higher cost because it follows Sherburne Road for approximately 800 feet. 3.0 Effects of Each Alternative

A review of the potential effects of each alternative on hydrology or streamflow in McDonnell Creek, fisheries and regulatory issues is provided in the following sections.

3.1 Hydrology The potential hydrologic effects of the alternatives are: a reduction in water supply for AID from McDonnell Creek with a corresponding increase in supply from the AID’s main canal diverting from the Dungeness River and a reduction in flow in McDonnell Creek resulting from reduced spills to the creek. Those potential effects are discussed in the following paragraphs. Water Supply from McDonnell Creek The AID holds water right for diversion from the creek for 5 cfs. The AID diverts both natural flow from McDonnell Creek and flow that is discharged from the Agnew Canal. The proportion of each is not known, but a much greater portion of the flow in the creek is provided by spills from Agnew Canal in late summer and a greater proportion of diversions is natural flow in the spring and early summer. Alternatives 1 and 2 will not result in any change in water supply from McDonnell Creek while Alternative 3 would result in a need to replace the diversions from



naturally occurring flow with flow diverted from the Dungeness River. Figure 4 shows the streamflow in McDonnell Creek for the April-October time period for 2003 and 2004. The data was obtained directly from the Department of Ecology Streamflow Monitoring website (https://fortress.wa.gov/ecy/wrx/wrx/flows/regions/state.asp). The location of the gaging site is directly downstream of the AID diversion from McDonnell Creek. AID’s peak water need at the diversion in 2004 was 3.5 cfs in June. Table 3-1 summarizes the bi-weekly averages of diversions from McDonnell Creek by AID. The periods listed in the table correspond to the time periods used in Chapter 6 of the CIDMP. Note that a partial record of flow diversions exists and additional data should be collected to verify the available data.

Figure 4. Streamflow for July-October in 2003 and 2004

Table 3-1

Bi-weekly Average Diversions from McDonnell Creek – 2004 Time Period April-

May June-July August

1-15 August 16-31

September 1-15

September 16-30

Average Diversion, cfs 2.1 2.7 2.1 1.7 1.2 0.8

0

1

2

3

4

5

6

7

8

9

10

4/1 4/15

4/29

5/13

5/27

6/10

6/24 7/8 7/2

2 8/5 8/19 9/2 9/1

69/3

010

/1410

/28

Date

Flow

rate

, cfs

McDonnell Creek 2003

McDonnell Creek 2004

AID Diversions 2004



The flow supplementation into McDonnell Creek is not precisely known however it varies from 0.5 to 2.5 cfs, according to AID records. The greatest percentage of supplementation to diversions occurs in July through September as natural streamflow in McDonnell Creek drops to low levels. During that time period, 0-2 cfs of natural streamflow may be diverted from McDonnell Creek with the remainder water discharged from the Agnew Canal. That portion of the diversion that is natural streamflow would need to be supplied through the Agnew Canal from its Dungeness River diversion. Potential Reduction in Flow in McDonnell Creek The flow in McDonnell Creek downstream of the diversion can be very low during the July-October time period and much of the flow in the creek at that point is likely contributed by AID discharges to the creek. It appears that 1 to 1.5 cfs is bypassed over the diversion dam (or its fish bypass) during the summertime. Alternatives 1 and 2 would not alter the current hydrologic regime. The effect of Alternative 3 would be to reduce the flow in McDonnell Creek from the point that it is discharged into the creek (about 1.5 miles upstream from the diversion dam) down to the diversion dam. The reduction in flow would be the amount discharged to McDonnell Creek, which is reported to be in the range of 0.5-2.5 cfs. A reduction in flow downstream of the diversion dam would also occur. The current low flow immediately downstream of the dam, as shown in Figure 4, is 1.3-1.5 cfs. The extent of the reduction in flow with Alternative 3 is not known, however the natural flow would likely drop below one cfs in late summer. Additional data should be collected to determine the amount of water discharged from the canal versus natural flow. A stream gauge located upstream of the AID spill into McDonnell Creek would provide sufficient data as streamflow and diversions are gauged downstream at the AID diversion. Spill from AID Canal Spillways on irrigation canals are used to balance inflow with demand. Since the Agnew Canal is long, it takes some time for changes in diversions to reach the point at which the canal crosses McDonnell Creek. Changing demands or inflow from stormwater along that long route creates the need to spill water to ensure the canal is not overtopped and washes out. One of their key spillways is to McDonnell Creek. The spillway is regularly used by AID to manage flow in the canals. Even with changes to operations that would occur with Alternative 3, spill will still occur to McDonnell Creek especially with stormwater input to the canal. Mix of Flow between McDonnell Creek Natural Flow and Agnew Canal Flow The mix of flow is an issue for false attraction of fish to McDonnell Creek that would normally return to the Dungeness River. Table 3-2 lists the percentage of flow discharged by AID to average monthly flow in McDonnell Creek. A range of flow for discharges is given using a range of discharges of about 0.5 to 2.5 cfs to the creek and average monthly flows for data available from the Ecology gage. The estimates do not include stormwater spilled from the canal. A wide range is provided because of the variability of natural flow. For the most part, discharge to McDonnell Creek is a small portion of the flow in the creek until the mid-June to mid-September time period when natural flows recede and supplementation of McDonnell Creek is required. In mid-September irrigation diversions taper off and most of the water in the creek is natural flow.



Table 3-2

Approximate Percent Mix of Flow in McDonnell Creek

Month Oct Nov Dec Jan Feb Mar Apr May June July Aug Sept

Ave Monthly Flow, cfs (includes discharge from AID)

19.4 36.7 35.0 27.7 17.1 10.1 9.1 9.3 8.8 4.2 3.6 4.0

% Agnew Canal

Discharge <5% <5% <5% <5% <5% <5% 5-

30%5-

30% 5-

30% 10-60%

10-60%

10-50%

3.2 Fisheries The CIDMP states “Anadromous salmonid stocks known to inhabit McDonnell Creek are coho salmon, winter steelhead and coastal cutthroat trout. McDonnell Creek was consistently supplemented with coho hatchery yearlings from 1952 until 1981. The other fish stocks are considered native runs. Anadromous fish have access to RM 5.2 where an impassable falls blocks further upstream migration”. That falls is located about 0.5 mile upstream of where AID spills water into the creek. Fish life history information indicates the mid-June to mid-September period of flow conveyance may influence late summer rearing of coho, steelhead and cutthroat juveniles and perhaps late emergence of steelhead fry. Augmented stream flows during summer months would also provide additional rearing space and improved carrying capacity between RM 2.0 and 5.0 compared to natural conditions. This action would benefit the future smolt yields of all three species if summer low flow rearing habitat is currently limiting the production potential. Conversely, rearing fish would imprint on a blended water source from mid-June to mid-September and a natural water source from mid-September to mid-June annually. Spawning adults return to McDonnell Creek in the fall and winter when flow conveyance is not occurring and natural flows exist except for a small diversion (0.5 to 1 cfs). There is speculation that juvenile fish, imprinting on a blended water source prior to emigration to marine waters, may not recognize the natural source upon subsequent return to freshwater as adults. Such a result could hinder future potential spawning escapement. Not enough data exist at this time to evaluate the potential for false attraction. WDFW has performed coho spawner surveys in McDonnell Creek since 1984 and steelhead spawner surveys since 1998. Randy Cooper of WDFW corresponded with us and related the following:

“During the surveys we try to sample all fish carcasses. Most of the time we come across very few salmon and steelhead carcasses during our surveys in McDonald Creek. Yes, we have seen some adipose clipped coho in McDonald



Creek; however, we have also seen a few marked coho in other streams that are not planted with hatchery coho. I am not sure this information will help you in answering your question regarding Dungeness fish straying into McDonald Creek. We have had several years of large coho returns to the Dungeness hatchery but did not see an unusually large number of coho redds in McDonald Creek.”

Flow conveyance in the creek has occurred routinely since 1927 and has not hindered the upward trend in stock abundance that has occurred in the creek since low returns in the mid-1980s. The mid-1980s was a period of dry weather patterns and poor ocean survival. Data that is needed to further evaluate the false attraction issue include:

Flow data upstream of the AID spill into McDonnell Creek Field data to determine if Dungeness River stocks are present or spawn in McDonnell

Creek.

3.3 Regulatory The regulatory issues for the alternatives are described below. Alternative 1 Alternative 1 would not significantly change the operation of the diversion, and not enough data is currently available to determine if there is a regulatory need to implement Alternatives 2 or 3 through the CIDMP process. However both the WDFW and JKT have expressed their preference to modify the dam or its operation and wish to start the process of implementing Alternatives 2 or 3, with Alternative 3 preferred. AID would prefer not to implement Alternatives 2 or 3 unless they can be built at no cost to the district but at the same time not divert funding that is needed to implement water conservation activities that are needed to meet flow diversion limits set in the CIDMP. Alternative 2 Permits for construction of the rock ramp fishway would need to be procured from WDFW and other agencies, notably the Corps of Engineers. The Corps would require a biological evaluation (BE) be completed. The issues discussed in this report would need to be described in the BE. Because it is a fish passage project and the AID has water rights for diversion, the permits would likely be issued. This alternative is the second preferred alternative by WDFW and JKT. Alternative 3 Permits for removal of the diversion structure would be required and the same process as described in Alternative 2 followed. Since it would be a dam removal project, approval would be fairly easy to obtain. The primary regulatory issue with this alternative is the use of Dungeness River water to replace the McDonnell Creek water supply. Although the additional diversion requirement would not have an impact on Dungeness River flow up to July because of snowmelt, an impact may occur in late August and early September when flows in the Dungeness River are not sufficient to meet instream flow goals. The additional diversion required is not known, as sufficient data on the natural streamflow in McDonnell Creek is not yet available. In Section 3.1, it is estimated up to 2 cfs additional flow would be required. An



additional diversion to meet the demands from McDonnell Creek may be difficult to obtain because of the efforts currently underway to reduce Dungeness River diversions during that same time period. Additional mitigation through water conservation projects would be needed to offset the additional diversions. The amount and cost of those projects has not been studied but will be before deciding to implement this alternative. 4.0 Costs

4.1 Alternative 1 The costs for Alternative 1 are small, as only small changes would be completed. Those changes could include extending the fish bypass pipeline and perhaps modifying the inlet to the fish ladder (at the downstream end of the dam).

4.2 Alternative 2 A cost estimate was prepared using assumed channel dimension and slopes, as detailed topographic information is not available at this time. The estimated cost is approximately $146,000. That cost includes the estimated construction costs, a 20% contingency and 25% addition for the cost of engineering, permitting, legal and administrative tasks. Sales tax is also added to the total. A cost estimate spreadsheet is included in Appendix I.

4.3 Alternative 3 Total project costs are estimated at $378,000 for Alternative A and $386,000 for Alternative B. Those costs include the estimated construction costs, a 20% contingency and 25% addition for the cost of engineering, permitting, legal and administrative tasks. Sales tax is also added to the total. Land acquisition/easement costs are included. A cost estimate spreadsheet is included in Appendix I. A cost not included in this estimate is the potential costs of mitigating the additional flow diversion required from the Dungeness River. Water conservation projects such as piping or reregulation reservoirs would be needed to offset the additional diversion. Those costs would be on the order of $500,000 per cfs saved based upon the cost and water savings of projects contained in the CIDMP. The total costs may then be an additional $1,000,000, depending on the water need determined in a study of natural flow of McDonnell Creek and spill from the Agnew canal. 5.0 Summary and Recommendations

Three alternatives were reviewed that have varying benefits and costs. Alternative 3 is the preferred alternative of WDFW and JKT, however it is the most costly. They prefer Alternative 2 to Alternative 1, as they would like to improve passage conditions at the dam. AID would prefer to maintain its existing operations but likely would not object to either Alternative 2 or 3 if funding were obtained for the project. The AID does not have adequate financial resources to implement either Alternative 2 or 3 by themselves. Before recommending a specific alternative, additional information is needed to determine the effects the existing operations have on fish, determine the amount of water that is needed from the Dungeness River to make up natural flow in McDonnell Creek, find and evaluate projects to mitigate the increased diversion need from the Dungeness River and determine if water rights



can be transferred to the McDonnell Creek water users from the Dungeness River. A list of information needed and actions to take follows.

Table 5-1 Information Needed and Actions Proposed

Information Needed Action Proposed

Natural Streamflow in McDonnell Creek and contribution of flow from Agnew Canal

Install stream gage on McDonnell Creek upstream of spill from Agnew Canal. Analyze new gage records and records from Ecology gages on McDonnell Creek and AID diversion to determine natural flow contribution and supplement from Agnew Canal.

Effect of supplemental flow on false attraction of listed salmonids

Spawning surveys or other studies that focus on Dungeness River stocks – the methodology of the survey should be designed by fisheries biologists (WDFW, JKT and representative of AID).

Potential projects that could conserve water and offset the water supplied by McDonnell Creek if Alternative 3 is implemented

Review list of water conservation actions and projects to identify projects beyond those needed to meet flow diversion schedules proposed in CIDMP.

Ability of AID to use additional water from Dungeness River during summer to offset loss of natural flow in McDonnell Creek if Alternative 3 is implemented.

Consult with Department of Ecology to determine if water rights on Dungeness River could be modified to allow diversion for existing McDonnell Creek water users in AID.

Availability of funding for implementation of either Alternatives 2 or 3

Prepare list of potential funding agencies and programs. Determine eligibility of Alternatives for funding, prepare applications if desired.

We recommend the actions proposed in Table 5-1 be started to provide agencies and the AID enough information to decide if Alternative 3 is warranted given its cost. If agencies and AID agree that Alternative 2 is a good course of action, it could be implemented prior to Alternative 3 if desired. Although that would increase the cost somewhat, much of the Alternative 3 project could remain in the creek even if the diversion is removed. Respectfully submitted, MONTGOMERY WATER GROUP, INC. Robert A. Montgomery, P.E. Principal Engineer

Cost Estimate for McDonnell Creek Diversion ImprovementsAlternative 2 - Rehabilitate Diversion Dam for Fish Passage with Rock Ramp

Item Description Quantity Unit Unit Cost Total Cost1 Mobilization 1 LS $5,000 $9,0003 Diversion of Water 1 LS $7,500 $7,5004 Erosion/Sedimentation Control 1 LS $3,000 $3,0005 Modifications to Dam 1 LS $3,000 $3,0007 Rock for Rock Ramp 2200 TONS $30 $66,0008 Site Restoration 1 LS $3,000 $3,000

Subtotal $91,500Contingency (20%) $18,300Total Construction Costs $109,800

Estimated Washington State Sales Tax (8.3%) $9,113Engineering, Legal and Administrative Fees (25%) $27,450Total Project Cost $146,363

Cost Estimate for McDonnell Creek Diversion ImprovementsAlternative 3A - Rehabilitate Irrigation System and Remove Diversion

Item Description Quantity Unit Unit Cost Total Cost1 Mobilization 1 LS $5,000 $21,000

Dam Removal2 Diversion of Water 1 LS $5,000 $5,0003 Erosion/Sedimentation Control 1 LS $3,000 $3,0004 Demolition and Removal of Existing Diversion 1 LS $5,000 $5,0005 Excavate Material Upstream of Dam 900 CY $30 $27,0006 Place Material (rock/gravel) Downstream of Dam 900 CY $10 $9,0007 Restore Channel Upstream of Dam 1 LS $10,000 $10,000

Irrigation Facility Upgrades8 18" PVC, 125 psi 2800 LF $36 $100,8009 New Gate/Measuring Structure at Agnew Canal 1 LS $5,000 $5,00010 Spillway to Matriotti Creek 1 LS $5,000 $5,00011 Improvements to Open Ditch 1 LS $25,000 $25,00012 New Gate and Inlet Structure for Pipe 1 LS $5,000 $5,000


Estimated Washington State Sales Tax (8.3%) $21,992Engineering, Legal and Administrative Fees (25%) $66,240Land Acquisition/Easement Costs $25,000Total Project Cost $378,192

Cost Estimate for McDonnell Creek Diversion ImprovementsAlternative 3B - Rehabilitate Irrigation System and Remove Diversion (New Pipe Alignment Along Sherburne Road)

Item Description Quantity Unit Unit Cost Total Cost1 Mobilization 1 LS $5,000 $21,000

Dam Removal2 Diversion of Water 1 LS $5,000 $5,0003 Erosion/Sedimentation Control 1 LS $3,000 $3,0004 Demolition and Removal of Existing Diversion 1 LS $5,000 $5,0005 Excavate Material Upstream of Dam 900 CY $30 $27,0006 Place Material (rock/gravel) Downstream of Dam 900 CY $10 $9,0007 Restore Channel Upstream of Dam 1 LS $10,000 $10,000

Irrigation Facility Upgrades8 18" PVC, 125 psi 2600 LF $36 $93,6009 Road Restoration (includes 6" base, 6-ft wide a.c.

pavement and saw cut)800 LF $15 $12,000

10 New Gate/Measuring Structure at Agnew Canal 1 LS $5,000 $5,00011 Spillway to Matriotti Creek 1 LS $5,000 $5,00012 Improvements to Open Ditch 1 LS $25,000 $25,00013 New Gate and Inlet Structure for Pipe 1 LS $5,000 $5,000


Estimated Washington State Sales Tax (8.3%) $22,470Engineering, Legal and Administrative Fees (25%) $67,680Land Acquisition/Easement Costs $25,000Total Project Cost $385,870

Appendix A Memo From Byron Rot, JKT

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