Water Use Planning was announced in 1996 to ensure provincial water management decisions reflect changing public values and environmental priorities. A Water Use Plan (WUP) is a technical document that, once approved by the provincial Comptroller of Water Rights, defines how water control facilities will be operated. The purpose of a Water Use Planning process is to develop recommendations defining a preferred operating strategy using a public participatory process.
Trout Creek Water Use Plan – Operating Agreement
District of Summerland. (2005). Trout Creek Water Use Plan Operating Agreement. Summerland: Prepared for District of Summerland.
The Trout Creek Water Use Plan Consultative Committee met in 2004 and in early 2005 to develop an Operating Agreement for the Trout Creek Reservoirs. The members included representatives from the District of Summerland, Ministry of Water, Land and Air Protection, Ministry of Agriculture, Food and Fisheries, Fisheries and Oceans Canada, Agricultural Water Users and the Penticton Indian Band
The steps that were taken in developing the proposed Operating Agreement for operation of the Trout Creek water supply system were as follows:
Each stakeholder on the Trout Creek Water Use Plan Consultative Committee presented their specific objectives in terms of their water requirements.
It was demonstrated by modelling the Trout Creek water supply over a 67-year period, that it was not feasible to meet the objectives of all stakeholders in full.
Operations for the “design drought” condition were incorporated in the modelling analysis to ensure that three consecutive years of drought could be managed.
Compromises were made until a feasible operating regime was developed. This was the basis of the Operating Agreement.
The Trout Creek watershed, which supplies most of Summerland’s water, has highly variable flows. They vary during the year and between the years. Drought years with very low flows pose special challenges for users. The water system developed by Summerland is fully allocated to current users. Domestic users, irrigators and fish have all taken a reduction in use to reach agreement on this Water Use Plan.
Summerland holds Water Licences to utilize approximately 15,000 acre feet of water per year from Trout Creek for irrigation and domestic purposes. The maximum use occurred in 1979 with consumption of 13,367 acre feet.
Summerland also holds Water Licences to store approximately 12,500 acre feet of water in 9 reservoirs within the Trout Creek watershed. Actual storage is calculated at 9,373 acre feet in all of the reservoirs combined. During the storage use season from July 1 to October 31 the maximum use was 7,695 acre-feet in 1979.
The Trout Creek aquatic ecosystem also requires water for sustainability, so is another important user of water. Specific flows are required in the creek to sustain fish populations, benthic invertebrates, and maintain a functional stream channel (sediment flushing, gravel recruitment, and development/maintenance of fish habitat features). As is the case with other water users, insufficient water can negatively impact the aquatic ecosystem and can risk sustainability when conditions are extreme.
Most years Summerland has lots of water for all users. It is the dry years that are critical for water use planning. The variability of the flows allows for different seasonal approaches to water use and an understanding of the different seasonal priorities is essential to the success of our efforts in sharing. A trigger graph model has been developed to set usage levels and to help predict periods of shortfall. When storage levels go below specified targets of storage volume over time, usage reductions must occur to ensure equitable sharing of the resource between users.
The required Summerland intake bypass flows in Trout Creek (fish flow) are based on the lesser of a multiplier of Camp Creek flows and fisheries conservation flows. Camp Creek is a tributary watershed of Trout Creek and the Camp Creek flow times a multiplier provides an index (but not an absolute value) of natural flow variations in Trout Creek. Seepage losses from the stream bed in Trout Creek are an additional source of uncertainty regarding natural flows in Trout Creek, particularly in drought years. It is important to note that at a given Camp Creek multiplier the fish flow releases in Trout Creek will reduce as Camp Creek flows decline through the summer.
Agricultural irrigation consumes an estimated 80% of the water used by Summerland. Increased crop water demand during drought years creates additional pressure on the water resource. The
Trout Creek hydrology model illustrates that it is simply not possible for the reservoir system to supply irrigation water demands equivalent to 2002 usage and fish flows equivalent to natural flows in Trout Creek during drought years.
For those who lack faith in computer models, the real life indicators of potential problems are storage levels, snowpack conditions and date of entry into use of storage water. The participants to this agreement are hopeful that the increased understanding gained from this process will help us manage this water system for the benefit of all.
Irrigators will conserve early season water to assist in ensuring that the full storage can meet peak crop water demand later in the season. The District will provide a water conservation officer that will work with irrigators to ensure responsible water use by all.
This Agreement recognizes the potential for a 10% increase in irrigation requirement due to global warming and a 9% potential increased draw if all Irrigation Roll commitments are met. Participants to this Agreement recommend increasing water storage in Trout Creek by raising Thirsk Dam to meet those challenges.