An Update on the Jordan River Flow Experiment

The current phase of the Jordan River flow experiment has been underway since 2015, but for various reasons
outlined below we have not been able to actually initiate the experiment. That has changed recently and we
wanted to bring you up to date. We will start with a brief discussion of the project background.

The Jordan River between Utah Lake and Farmington Bay is currently listed as an impaired water body due to
several water quality parameters including E. coli, temperature, total dissolved solids, nutrients, metals, and
low levels of dissolved oxygen (DO). The Jordan River downstream of 2100 South (lower Jordan River) has
been carefully studied in the past due to low DO. The EPA approved the first phase of a Total Maximum Daily
Load (TMDL) study in 2013 that identified organic matter (OM) as a water quality pollutant leading to low DO
levels in the river. The TMDL recommended additional steps to identify sources of OM and other processes
that were known to influence DO levels.

Based in part on these recommendations, River Network commenced a study in 2013 of flow management
options for the lower Jordan River. The intent of the study was to enhance efforts to increase DO and meet
water quality standards while also improving ecosystem function. This effort analyzed existing data along with
flow and water quality models used in the TMDL. The results of this study indicated a complex relationship
between flow and DO during dry baseflow conditions. The decision was made to continue the study with a
series of flow experiments.

From 2015 to the present, the Jordan River Commission (Commission) worked to secure water rights to
implement the recommended flow experiments. During this time, the Commission met with the Technical
Advisory Team (TAT) to provide information and progress updates on the experiment. We also completed a
comprehensive review of available continuous DO and flow measurements from 2011–2016. This review
identified DO response to a range of flow changes (including flow increase and decrease) during non-storm
periods. Variability in DO response confirmed the complexity of the DO/flow relationship identified by earlier
research. However, flow increases during summer months consistently showed a positive DO response, even
with minor flow increases.

Kennecott Utah Copper LLC recently agreed to temporarily provide 60 cubic feet/second (cfs) in support of the
flow experiments during August and September of this year. Two different types of flow experiments are
scheduled including pulse and ramp-up experimental designs (see attached calendar for proposed schedule). A
minimum of three days baseflow will occur between each experiment to allow conditions to stabilize. The
proposed schedule could be adjusted due to precipitation events that occur between flow experiments.
Additional flow will be diverted to the lower Jordan River at the 2100 South diversion structure, and all flow
increases or decreases will occur between 9:00 a.m. and noon. Pulse experiments will last for three days and
begin with a flow increase of 60 cfs on the first day. Flow will be maintained at this level for the next 72 hours
and return to baseflow conditions at approximately the same hour as the initial flow increase.

Ramp-up experiments will last for a total of 17 days. The initial flow increase will be 30 cfs maintained for 72
hours, followed by a second increase of 30 cfs on the fourth day of the experiment. Flow will be maintained at
60 cfs above baseflow conditions for 10 consecutive 24-hour periods. After this time, flows will return to
baseflow with a 30 cfs decrease maintained for 72 hours, followed by a second decrease of 30 cfs. A total of
three pulse and one ramp-up experiments are scheduled to occur this year.

Notifications of flow changes will be posted on the Jordan River Commission website
( three days prior to the start of any experiment. Individual communication
will take place with members of the TAT at this time through email or phone. Any questions with the proposed
schedule or experimental design can be answered by contacting Cirrus. Contact information is provided below.

Cirrus Ecological Solutions
Eric Duffin
(435) 787-1490