Please send comments on this plan to the below email address.

mailto:robby.mcdonald@nahydro.com

HATFIELD HYDRO RECREATIONAL FLOW RELEASE PLAN

May 30th, 2007

DRAFT

            The Hatfield Hydroelectric project withdraws water from the Black River at the dam via a three-mile long hydroelectric power canal.  The power canal operates at a normal level that is three feet lower than summer pool behind the dam of Lake Arbutus.  The three-mile long power canal has become a complex water conveyance with extensive developed shoreline due to real estate development on side channels.  The power canal is perched and has stability issues that limit its maximum water level.  A manually adjusted control gate between Lake Arbutus and the power canal compensates for varying turbine flows and is used to maintain the power canal at its maximum safe level three feet lower than the summer pool of Lake Arbutus. 

            The license for the Hatfield Hydroelectric project requires the project to provide flows during certain periods into the bypassed reach (natural river channel) of the Black River, the river section down stream from the dam and up stream of the power house.  This section of river drops 90 feet in 3.25 miles and provides class-1 through class-5 white water during flows typically encountered during a normal water year. 

            The bypassed reach of the Black River has a minimum of 75 cubic feet per second (cfs) of water flow in it at all times unless inflow to the Lake Arbutus is less than 75 cfs.  The water flow is maintained by either of two bypass turbine units rated as 75 cfs each located at the Hatfield Dam.  The main generating units in the power house utilize the next1, 200 cfs of river flow, discharging this flow to the area immediately down stream of the power house.  In December of 2007 an additional 62 cfs, 400 KW generating unit will be in service in the main power house bringing the total generating flow capacity to 1,262 cfs.

          The Hatfield Hydroelectric project license requires five recreational releases per year to the bypassed reach of the Black River.  However, the current release plan is ineffective and unsatisfactory to all parties because the flow regime was, in retrospect, excessively conservative with unrealistic flow requirements for the release peak flows and down ramp causing infrequent and inconsistent releases. 

            Kayakers have been disappointed by release cancellations caused by the inappropriately designed flow regime, which was ill-suited for the flashy Black River watershed.  Scheduled releases frequently would be cancelled by Thursday or Friday due to low flow conditions.  Initially flow releases attracted up to 35 kayakers per release, drawing boaters from the Twin Cities, Chicago, southern Wisconsin, and northern Iowa.  Because boaters have become frustrated with inconsistent and unreliable releases and a series of drought years, the number of users tapered off over the years.

            Due to dissatisfaction with the existing recreational release plan, NAH, National Park Service (NPS), Wisconsin Department of Natural Resources (WDNR), Friends of Black River, and white water boaters propose an improved release plan that would:

1.                  Reduce flow trigger points to predictable levels guaranteeing availability,

giving consistency to the program.

2.                  Have three releases per year, one each in May, June, and September; eliminate releases in the low water months of July and August.

3.                  In 2007, flows will be controlled between 400 and 600 CFS; this range will be revaluated on an annual basis by the review committee.

          The proposed recreational release plan improves safety and project operating conditions at the Hatfield Project by allowing the hydroelectric capacity at the main generating station to decrease rather than cease, thereby improving project owners’ ability to limit hydraulic stress to the power canal.

          The storage capacity of Lake Arbutus would be utilized within project operating parameters, to an increasing degree as river flow was not available, to make up the minimum flow requirement of the planned recreational release. Flow ramping rates will be evaluated by the review committee such to stimulate natural precipitation and resulting flow events in this region.

            Recreational releases are proposed for the third Saturday in May, June, and September. The flow of the Black River would have to be at least 150 CFS as measured by the Nielsville flow gage at least 24 hours in advance of the event in order for the event to be held.  The proposed plan is described in more detail:

1.                  Flows in the Black River excess of 150 CFS trigger the event.

2.                  Inflows above 150 CFS and below 1200 CFS allow release of flows 400-600 CFS of varying peak durations.  The target peak flow duration is three hours.  Lake levels will be kept within the existing license operating band of four inches.

3.                  Ramping rates in the dewatered reach of the Black River would be        maintained at 300 cfs/hr rising limb and 100 cfs/hr falling limb. 

4.                  In 2007, flows above 1200 CFS will be directed into hydro turbines allowing the release flow to remain constant.  The range of 400-600 cfs will be revaluated on an annual basis by the parties to assess the feasibility of increasing the upper flow limit until parties are satisfied. 

5.                  Releases will be scheduled for the third Saturday in May, June, and September from 11:00 a.m. to 2:00 p.m.

6.                  NAH, NPS, and WDNR and Friends of Black River would monitor plan performance.  NAH will convene the review committee in late winter (January – March) for this assessment.    

7        NAH’s flow hotline will be consistently accurate and reliable; NAH will work with Friends of the Black River to define wording.

8        NAH will continue to post sign-in sheets and monitor use.

9        NAH will make a vault toilet available at power house location.

          NAH proposes to monitor the performance of the proposed recreational release plan and revisit the subject prior to the recreational season in 2008 and annually thereafter until all parties achieve consensus on the upper flow release limit that is practical and feasible.  The performance of the proposed plan and recommended changes will be discussed with the plan committee consisting of Friends of the Black River, NPS, WDNR, and NAH. 

          The power canal is perched and in unstable terrain.  The changing flow regimen caused by flow diversion to river and then back to the power canal during a release causes additional monitoring of canal berm pizometers, seepage flow, and level stabilization efforts following the release. 

          NAH will offer the draft plan to Lake Arbutus Lake Association for their review.