HomeMy WebLinkAboutItem No. 5(".1 01 <�
1, A' eL
REPORT TO CITY COUNCIL
TO: HONORABLE MAYOR AND COUNCILMEMBERS
FROM: GRANT YATES, CITY MANAGER
DATE: APRIL 23, 2013
SUBJECT: A RESOLUTION OF THE CITY COUNCIL OF THE CITY
OF LAKE ELSINORE, CALIFORNIA, APPROVING THE
IN -LAKE SEDIMENT NUTRIENT REDUCTION PLAN
SUBMITTED BY THE LAKE ELSINORE /CANYON
LAKE TMDL TASK FORCE TO THE REGIONAL
WATER QUALITY CONTROL BOARD
Recommendation
Staff recommends the City Council approve the attached resolution in support of the
"In -Lake Sediment Nutrient Reduction Plan for Lake Elsinore" submitted by the
TMDL Task Force and adopted by the California Regional Water Quality Control
Board.
Background
Lake Elsinore is the largest natural freshwater lake in southern California and is
listed as impaired by nutrients under the Federal Clean Water Act's 303d listing.
The Santa Ana Regional Water Quality Control Board promulgated a Total Maximum
Daily Load (TMDL) program for Lake Elsinore in 2005 to limit nutrient input and to
correct the water impairment.
As part of the TMDL Program, the named stakeholders are required to develop and
submit a plan for controlling nutrients to attain compliance with the specified water
quality targets for Lake Elsinore. In order to pool resources a stakeholders group
was formed in 2006 and culminated in the formation of the TMDL Task Force
Agreement. Below is a list of the current TMDL Task Force Member Agencies.
TMDL Task Force Members
➢ State of California:
• Santa Ana Regional Water Quality Control Board, Department of Fish
and Wildlife and Department of Transportation.
➢ March Air Reserve Base and March JPA
➢ County of Riverside
➢ Riverside County Flood Control and Water Conservation District
➢ Cities:
AGENDA ITEM NO. 5
Page 1 of 37
Resolution TMDL Task Force
Page 2 of 2
April 23, 2013
• Lake Elsinore, Canyon Lake, Perris, Moreno Valley, Riverside, Hemet,
Murrieta, San Jacinto, Menifee, Wildomar and Beaumont.
➢ Water Agencies:
• Eastern Municipal Water District
• Elsinore Valley Municipal Water District
➢ Agriculture — Represented by the Western Riverside County Agricultural
Coalition
• Concentrated Animal Feeding Operators
• Agricultural Operators
The cost to implement conventional nutrient control measures to reduce nutrients
throughout the entire Lake Elsinore /San Jacinto River Watershed to the degree
required to meet Federal and State water quality targets for Lake Elsinore may be
cost prohibitive. For instance, the "DRAFT Comprehensive Nutrient Reduction Plan
(2012)" prepared by the Riverside County Flood Control & Water Conservation
District estimated a total cost for conventional nutrient control in the watershed could
range from $500 million to $2 billion.
Alternatively, a combination of limiting nutrients in the watershed to the maximum
extent practicable, lake aeration /mixing systems, lake -level stabilization and
biomanipulation of the fishery may be the most rapid and low cost approach to
achieve the water quality targets. The TMDL Task Force embraced this low cost
approach by developing the "In -Lake Sediment Nutrient Reduction Plan ", which was
adopted by the Santa Ana Regional Water Quality Control Board in November 2007.
Discussion
Discussions are currently underway with watershed stakeholders to voluntarily fund
in -lake treatments to assist in complying with the TMDL program. It would be
instructive for stakeholders and staff if the City Council expressed its support of the
TMDL Task Force's low cost and whole -lake approach (Lake Stabilization,
Aeration /Mixing Systems & Fisheries Management) to achieving the TMDL water
quality targets for Lake Elsinore.
Fiscal Impact
None.
Approved by: Pat Kilroy, Director
Lake, Parks & Recreation Department
Approved by: Grant Yates, City Manager
Attachments:
• Resolution
• In -Lake Sediment Nutrient Reduction Plan for Lake Elsinore
Page 2 of 37
RESOLUTION NO. 2013 -017
A RESOLUTION OF THE CITY COUNCIL OF THE CITY
OF LAKE ELSINORE, CALIFORNIA, APPROVING THE IN-
LAKE SEDIMENT NUTRIENT REDUCTION PLAN
SUBMITTED BY THE LAKE ELSINORE /CANYON LAKE
TMDL TASK FORCE TO THE REGIONAL WATER
QUALITY CONTROL BOARD
WHEREAS, Lake Elsinore is the largest natural freshwater lake in
southern California;
WHEREAS, the City is required by the State of California to maintain the
Lake for public park and recreation purposes in perpetuity; and
WHEREAS, Lake Elsinore is listed on the Federal Clean Water Act 303d
list as impaired by nutrients; and
WHEREAS, the TMDL Task Force, representing the majority of
stakeholders in the watershed, developed an "In -Lake Sediment Nutrient Reduction
Plan for Lake Elsinore (2007)" as a low cost alternative to compliance with the TMDL
Program to achieve the water quality targets for Lake Elsinore ; and
WHEREAS, the Santa Ana Regional Water Quality Control Board
evaluated and adopted the TMDL Task Force's "In -Lake Sediment Nutrient Reduction
Plan for Lake Elsinore" in November 2007; and
NOW, THEREFORE, THE CITY COUNCIL OF THE CITY OF LAKE
ELSINORE DOES HEREBY RESOLVE AND ORDER AS FOLLOWS:
Section 1 By adoption of this resolution the City hereby supports the low cost
and whole -lake approach to achieving the TMDL water quality targets for Lake Elsinore
as contained in the "In -Lake Sediment Nutrient Reduction Plan for Lake Elsinore (2007)"
prepared by the TMDL Task Force and adopted by the Regional Water Quality Control
Board.
PASSED, APPROVED AND ADOPTED at a regular meeting of the City
Council of the City of Lake Elsinore, California, this 23`d day of April 2013.
Robert E. Magee, Mayor
ATTEST:
Virginia J. Bloom, City Clerk
APPROVED AS TO FORM:
Barbara Zeid Leibold, City Attorney
Page 3 of 37
California Regional Water Quality Control Board
Santa Ana Region
RESOLUTION NO. 118- 2007 -0083
Resolution Approving Plans and Schedules Submitted by the Canyon Lake /Lake Elsinore
TMDL Task Force and Individual Discharger Groups Pursuant to the Lake Elsinore and
Canyon Lake Nutrient Total Maximum Daily Loads Specified in the Water Quality Control
Plan for the Santa Ana River Basin
WHEREAS, the California Regional Water Quality Control Board, Santa Ana Region
(hereinafter Regional Board), finds that:
1. An updated Water Quality Control Plan for the Santa Ana River Basin (Basin Plan) was
adopted by the Regional Board on March 11, 1994, approved by the State Water Resources
Control Board (SWRCB) on July 21, 1994, and approved by the Office of Administrative Law
(OAL) on January 24, 1995.
2. Amendments to the Basin Plan to incorporate Lake Elsinore and Canyon Lake Nutrient Total
Maximum Daily Loads (TMDLs) were approved by the Regional Board on December 20,
2004, by the State Water Resources Control Board on May 19, 2005, by the Office of
Administrative Law on July 26, 2005 and by the US Environmental Protection Agency on
September 30, 2005.
3. The Lake Elsinore and Canyon Lake Nutrient TMDLs were developed in accordance with
Clean Water Act Section 303(d) and the California Water Code, Division 7, Chapter 4,
Article 3, Section 13240 at seq. The amendment is incorporated into Chapter 5
"Implementation ", of the Basin Plan.
4. Responsible agencies and dischargers in the Lake Elsinore /Canyon Lake watershed have formed
a Lake Elsinore and Canyon Lake TMDL Task Force (TMDL Task Force), The TMDL Task Force
members are working jointly to implement requirements of the Lake Elsinore and Canyon Lake
Nutrient TMDLs, TMDL Task Force members include the following agencies /parties: the US
Forest Service, the US Air Force (March Air Reserve Base), March Joint Powers Authority,
California Dept. of Transportation (Caltrans), California Dept. of Fish and Game, the County of
Riverside, the Riverside County Flood Control and Water Conservation District, Eastern Municipal
Water District, Elsinore Valley Municipal Water District, Western Riverside County Agricultural
Coalition, and the cities of Lake Elsinore, Canyon Lake, Hemet, San Jacinto, Perris, Moreno
Valley, Murrieta, Riverside and Beaumont.
5. The Regional Board is a signatory to the Task Force Agreement and serves as an advisory
member of the TMDL Task Force.
6. The Lake Elsinore and Canyon Lake Nutrient TMDLs, Task 5 - Agricultural Activities
requires the agricultural operators within the Lake Elsinore and Canyon Lake watershed to
submit a proposed Nutrient Management Plan (NMP) by September 30, 2007,
Page 4 of 37
Resolution No. R8- 2007 -0083
Page 2 of 4
7. In compliance with the Task 5 — Agricultural Activities, by letter dated September 12, 2007
and on behalf of agricultural operations in the San Jacinto River watershed, including
confined animal feeding operators, the Western Riverside County Agricultural Coalition
(WRCAC), submitted for Regional Board review and approval a proposed plan and schedule
for development of the Agricultural Nutrient Management Plan.
8. The Regional Board has reviewed the proposed plan and schedule for development of the
Agricultural Nutrient Management Plan and finds that it complies with the applicable
requirements of the Lake Elsinore and Canyon Lake Nutrient TMDLs specified in the Basin
Plan.
9. The Lake Elsinore and Canyon Lake Nutrient TMDLs, Task 8 - Forest Area — Identification
of Forest Lands Management Practices requires the US Forest Service to submit by
September 20, 2007 for Regional Board review and approval, a plan with a schedule for
identification, development and implementation of Management Practices to reduce nutrient
discharges emanating from the Cleveland National Forest and the San Bernardino National
Forest.
10. In compliance with Task 8 - Forest Area — Identification of Forest Lands Management, by
letter dated September 27, 2007, the San Bernardino National Forest staff submitted a
proposed list of the existing Forest Plans that are pertinent to achieve compliance with the
TMDL requirements, and a list of BMP evaluation /monitoring reports. The submittal
addresses Forest Plans for both the San Bernardino and Cleveland National Forests.
Additional information submitted by the Forest Service on October 25, 2007, includes
requested information on BMP effectiveness monitoring.
11. The Regional Board has reviewed the Forest Service existing projects and supplemental
information provided and finds that the Forest Service submittal complies with the applicable
requirements of the Lake Elsinore and Canyon Lake Nutrient TMDLs specified in the Basin
Plan.
12. The Lake Elsinore and Canyon Lake Nutrient TMDLs, Task 9 - Lake Elsinore Sediment
Nutrient Reduction Plan requires all dischargers to submit by March 31, 2007 for Regional
Board review and approval a proposed plan and schedule for reduction of in -lake sediment
nutrient toads for Lake Elsinore.
13. In compliance with Task 9 - Lake Elsinore Sediment Nutrient Reduction Plan, by letter dated
November 1, 2007, the Lake Elsinore /Canyon Lake TMDL Task Force, submitted for
Regional Board review and approval a final In -Lake Sediment Nutrient Reduction Plan. The
Plan includes existing projects and new strategies to improve water quality in Lake Elsinore,
compliance monitoring (both water quality and biological), and an implementation schedule.
14. The Regional Board has reviewed the proposed Lake Elsinore in -lake nutrient reduction
plan and schedule and finds that it complies with the applicable requirements of the Lake
Elsinore and Canyon Lake Nutrient TMDLs specified in the Basin Plan.
15. The Lake Elsinore and Canyon Lake Nutrient TMDLs, Task 10 - Canyon Lake Sediment
Nutrient Treatment Evaluation Plan requires specified nutrient dischargers to submit by
Page 5 of 37
Resolution No. RB -2007 -0083
Page 3 of 4
March 31, 2007 for Regional Board review and approval a proposed plan and schedule for
evaluating in -lake sediment nutrient treatment strategies for Canyon Lake.
16. In compliance with Task 10 — Canyon Lake Sediment Nutrient Treatment Evaluation Plan,
by letter dated June 25, 2007, the San Jacinto River Watershed Council submitted for
Regional Board review and approval a proposed Canyon Lake in -lake nutrient sediment
evaluation plan. Additional model analysis is being conducted by the TMDL Task Force to
ensure that the proposed nutrient sediment reduction alternatives would achieve compliance
with the TMDL targets and to develop an implementation schedule. The model analysis is
expected to be completed by December 2007.
17. The Regional Board has reviewed the proposed Canyon Lake in -lake nutrient treatment
evaluation plan and the proposed plan to conduct additional model analysis and develop an
implementation schedule. The proposed plans will comply with the applicable requirements
of the Lake Elsinore and Canyon Lake Nutrient TMDLs specified in the Basin Plan.
18. The Lake Elsinore and Canyon Lake Nutrient TMDLs, Task 11- Update of Watershed and
In -Lake Nutrient Models requires all nutrient dischargers to submit by March 31, 2007 for
Regional Board review and approval a proposed plan and schedule for updating the existing
Lake Elsinore /San Jacinto River Nutrient Watershed Model and the Canyon Lake and Lake
Elsinore in -lake models.
19. In compliance with Task 11 — Update of Watershed and In -Lake Nutrient Models, by letter
dated November 1, 2007, the TMDL Task Force submitted for Regional Board review and
approval a proposed plan and schedule for update of the watershed and in -lake water
quality models.
20. The Regional Board has reviewed the proposed plan and schedule for Update of Watershed
and In -Lake Nutrient Models and finds that it complies with the applicable requirements the
Lake Elsinore and Canyon Lake Nutrient TMDLs specified in the Basin Plan.
21. The Lake Elsinore and Canyon Lake Nutrient TMDLs, Task 12 - Pollutant Trading Plan
requires specified dischargers to submit by September 30, 2007 for Regional Board review
and approval a proposed Pollutant Trading Plan.
22. In compliance with Task 12 — Pollutant Trading Plan, by letter dated November 1, 2007, the
TMDL Task Force submitted for Regional Board review and approval a proposed plan and
schedule for development of a pollutant trading plan.
23. The Regional Board has reviewed the proposed Pollutant Trading Plan and schedule and
finds that it complies with the applicable requirements of the Lake Elsinore and Canyon
Lake Nutrient TMDLs specified in the Basin Plan
NOW, THEREFORE, BE IT RESOLVED THAT:
1. The Regional Board approves the following plans and schedules as set forth in the
attachments:
Page 6 of 37
Resolution No. R8- 2007 -0083
Page 4 of 4
Attachment A — Agricultural Nutrient Management Plan
Attachment B — Forest Service Land Practices Identification
Attachment C — Lake Elsinore Sediment Nutrient Reduction Plan
Attachment D — Canyon Lake Sediment Nutrient Treatment Evaluation Plan
Attachment E — Watershed and In -Lake Nutrient Models Update Plan
Attachment F — Pollutant Trading Plan
2. These plans comply with the respective requirements of the Lake Elsinore and Canyon Lake
Nutrient TMDLs specified in the Basin Plan.
3. Agricultural operators, the US Forest Service and members of the TMDL Task Force are in
compliance with the Lake Elsinore and Canyon Lake Nutrient TMDLs.
4. These plans and schedules must be implemented upon Regional Board approval.
I, Gerard J. Thibeault, Executive Officer, do hereby certify that the foregoing is a full, true
and correct copy of a resolution adopted by the California Regional Water Quality Control Board,
Santa Ana Region, on November 30, 2007.
Gerard J. Thibeault
Executive Officer
Page 7 of 37
In -Lake Sediment Nutrient Reduction Plan
for
Lake Elsinore
Submitted to:
California Regional Water Quality Control Board — Santa Ana Region
Submitted by:
Lake Elsinore/Canyon Lake TMDL Task Force
October 31, 2007
Page 8 of 37
Page 9 of 37
List of Figures
Figure A:
Lake Elsinore in Riverside County, California
Figure B:
Biological Benefits of Lake Level Stabilization
Figure C:
Biological Benefits of In -Lake Aeration and Mixing
Figure D:
Biological Benefits of Targeted Fisheries Management
Figure E:
Adaptive Management to Protect Lake Elsinore
Figure F:
TMDL Review Process
List of Tables
Table 1:
Biological and Physical Indicators for Lake Elsinore
Table 2:
Water Chemistry Indicators for Lake Elsinore
Table 3:
TMDL Allocations for Lake Elsinore
Table 4:
Source Allocations for Nitrogen in Lake Elsinore
Table 5:
Source Allocations for Phosphorous in Lake Elsinore
Table 6:
Nutrient Management Plans for External Sources to Lake Elsinore
Table 7:
Estimated External Phosphorus Loads to Lake Elsinore (1993 -2004)
Table 8:
Key Studies Used to Evaluate and Select Nutrient Reduction Strategies
Table 9:
In -Lake Water Quality Monitoring Program for Lake Elsinore
Table 10:
Recommended Biological Monitoring Program for Lake Elsinore
Table 11:
Water Quality Monitoring Reports for Lake Elsinore
Table 12:
Schedule for Lake Elsinore In -Lake Sediment Nutrient Reduction Plan
In -Lake Sediment Nutrient Reduction Plan for Lake Elsinore Page 3 of 30
Page 10 of 37
1.0 Background
Lake Elsinore is located approximately 60 miles southeast of downtown Los Angeles (see Fig.
A). It has a surface area of approximately 3,000 acres and a mean depth of approximately 13 ft.
The lake provides aquatic habitat for a variety of freshwater species and recreational
opportunities for a large number of people living throughout southern California.
Figure A: Lake Elsinore in Riverside County, California
In 1998, the Santa Ana Regional Water Quality Control Board added Lake Elsinore to the 303(d)
list of impaired water bodies because it is eutrophic. Excessive algal blooms and low dissolved
oxygen levels are caused by elevated nutrient (e.g. nitrogen and phosphorus) concentrations in
the water column. These conditions, in turn, cause recurring fish kills and other noxious
conditions in the lake.
In -Lake Sediment Nutrient Reduction Plan for Lake Elsinore Page 4 of 30
Page 11 of 37
i
ti
t
,...
T. ..
San 7acinto Watershed
a
In 1998, the Santa Ana Regional Water Quality Control Board added Lake Elsinore to the 303(d)
list of impaired water bodies because it is eutrophic. Excessive algal blooms and low dissolved
oxygen levels are caused by elevated nutrient (e.g. nitrogen and phosphorus) concentrations in
the water column. These conditions, in turn, cause recurring fish kills and other noxious
conditions in the lake.
In -Lake Sediment Nutrient Reduction Plan for Lake Elsinore Page 4 of 30
Page 11 of 37
For several years, the Regional Board worked closely with stakeholders to identify and quantify
all natural and anthropogenic sources of nutrients in the watershed. In 2004, the Regional Board
relied on results from these on -going investigations to adopt a Total Maximum Daily Load
(TMDL) to control nitrogen and phosphorus concentrations in Lake Elsinore.' The TMDL was
subsequently approved by the State Water Resources Control Board and by the U.S.
Environmental Protection Agency.
The TMDL Implementation Plan enacted by the state and federal regulatory authorities requires
point and non -point dischargers in the watershed to develop and submit an "In -Lake Sediment
Nutrient Reduction Plan" for Lake Elsinore .4 The purpose of the plan is to describe a long -term
strategy to control nutrients released from in -lake sediments.
2.0 Goals and Outcomes
The foremost goal of the TMDL process is to protect the designated beneficial uses of Lake
Elsinore. Therefore, the intended outcome is to achieve the level of water quality needed to
support warm water aquatic habitat and recreational activities; at a minimum, this includes
preventing excessive algae growth, dissolved oxygen depletion and fish kills in the lake. The
Regional Board set forth specific indicators by which to measure successful implementation of
the TMDL (see Table 1).
Table 1: Biological and Physical Indicators for Lake Elsinore5
Indicator
Interim Target (by 2015)
Final Target (by 2020)
Summer average no greater than
Summer average no greater than 25
Chlorophyll -a (algae)
40 ug /L
mg/L
Depth average no less than 5
No less than 5 mg/L at one meter
Dissolved Oxygen
mg/L across all depths
above the lake bottom
California Regional Water Quality Control Board 98 - Santa Ana Region; Resolution No. RS- 2004 -0037 (Dec.
20, 2004).
s California State Water Resources Control Board; Resolution No. 2005 -0038 (May 19, 2005).
U.S. EPA Approval Letter dated September 30, 2005
The Lake Elsinore In -Lake Nutrient Reduction Plan is identified as Task #9 in Table 5 -9s on page 7 of 21 of the
TMDL (Resolution No. R8 -2004- 0037).
Source: Table 5 -9n on page 2 of 21 of Resolution No. R8- 2004 -0037.
In -Lake Sediment Nutrient Reduction Plan for Lake Elsinore Page 5 of 30
Page 12 of 37
It is expected that if the targets for dissolved oxygen and Chlorophyll -a can be met, then the fish
kills and other aesthetic impairments to recreational uses will be virtually eliminated. It is also
assumed that nutrient concentrations in the water column must be significantly reduced in order
to achieve the desired outcome. Therefore, the Regional Board also adopted numeric targets for
certain chemical concentrations in Lake Elsinore (see Table 2). These chemical targets were
intended to ensure compliance with the Basin Plan's narrative water quality objectives that
prohibit the discharge of substances that cause excessive algae growth or other nuisance
conditions.
Table 2: Water Chemistry Indicators for Lake Elsinore
Indicator
Final Target Concentration (by 2020)
Total Phosphorus
Annual average no greater than 0.10 mg/L
Total Nitrogen
Annual average no greater than 0.75 mg /L
Ammonia - Nitrogen
Equation -based on Temperature & pH
In order to meet the physical, chemical and biological target values established in the TMDL, the
Regional Board supported development of water quality models to estimate the assimilative
capacity for nitrogen and phosphorus in Lake Elsinore.8 These models, developed by Tetra
Tech, Inc. and Dr. Michael Anderson, were used to establish load allocations for non -point
sources and wasteload allocations for point sources (see Table 3).
Table 3: TMDL Allocations for Lake Elsinore9
Note: all source allocations are expressed as 10 year running averages.
G Regional Water Quality Control Board - Santa Ana Region. Water Quality Control Plan - Santa Ana River Basin
(8). Resolution No. R8 -1994 -0001 (March It, 1994). See page 4 -5.
Source: Table 5 -9n on page 2 of 21 of Resolution No. R8- 2004 -0037.
e TetraTech Inc. Lake Elsinore and Canyon Lake Nutrient Source Assessment. 2003.
9 Source: Table 5 -9n on page 2 of 21 of Resolution No. R8- 2004 -0037.
In -Lake Sediment Nutrient Reduction Plan for Lake Elsinore Page 6 of 30
Page 13 of 37
Phosphorus
Nitrogen
Current Loading
64,923 kg/yr
345,689 kg /yr
Allowed Loading
28,584 kg/yr
239,025 kg/yr
Net Excess Load
36,339 kg/yr
106,664 kg/yr
Required Reduction
56%
31%
Note: all source allocations are expressed as 10 year running averages.
G Regional Water Quality Control Board - Santa Ana Region. Water Quality Control Plan - Santa Ana River Basin
(8). Resolution No. R8 -1994 -0001 (March It, 1994). See page 4 -5.
Source: Table 5 -9n on page 2 of 21 of Resolution No. R8- 2004 -0037.
e TetraTech Inc. Lake Elsinore and Canyon Lake Nutrient Source Assessment. 2003.
9 Source: Table 5 -9n on page 2 of 21 of Resolution No. R8- 2004 -0037.
In -Lake Sediment Nutrient Reduction Plan for Lake Elsinore Page 6 of 30
Page 13 of 37
The Santa Ana Regional Water Quality Control Board recognized that many different sources
were contributing nutrient loads to Lake Elsinore. Consequently, maximum average loads were
specified, by source, within the TMDL for both nitrogen (see Table 4) and phosphorus (see
Table 5).t0 However, the TMDL does not require reductions in nitrogen loads from in -lake
sediments because the Regional Board staff lacked sufficient data to calculate appropriate load
allocations and wasteload allocations for nitrogen." Additional studies are underway because
control of nitrogen releases from sediment is likely to be important in order to ensure un- ionized
ammonia toxicity does not cause or contribute to fish kills in the future. These studies are
discussed in Section 4.3 of this Plan.
Table 4: Source Allocations for Nitrogen in Lake Elsinore
Source
Current
Load
Allowed
Load
Net
Difference
Pct.
Reduction
Internal Sediment
197,370 kg/yr
197,370 kg/yr
0 kg/yr
0%
Atmospheric Deposition
11,702 kg /yr
11,702 kg/yr
0 kg/yr
0%
Supplemental Water
59,532 kg/yr
7,442 kg/yr
52,090 kg/yr
87%
Septic Systems
1,058 kg/yr
608 k yr
450 kg/yr
43%
Urban Runoff
606 kg/yr
349 kg/yr
257 kg/yr
42%
Open or Forest Land
567 kg/yr
567 kg/yr
0 kg/yr
0 0
Agriculture
371 kg /yr
213 kg/yr
158 kg/yr
43%
Outflow from Canyon Lake
25,547 kg/yr
20,774 kg/yr
4,773 kg/yr
19%
Total
296,753 kg/yr
i 239,025 kg/yr
57,528 kg/yr
19%
Table 5: Source Allocations for Phosphorus in Lake Elsinore
Source
Current
Load
Allowed
Load
Net
Difference
Pct.
Reduction
Internal Sediment
33,160 kg/yr
21,554 kg/yr
11,606 kg /yr
35%
Supplemental Water
14,883 kg/yr
3,721 kg/yr
11,162 kg/yr
75%
Open or Forest Land
178 kg/yr
178 kg/yr
0 kg /yr
0%
Urban Runoff
124 k yr
124 kg/yr
0 kg/yr
0%
Atmospheric Deposition
108 kg/yr
108 kg/yr
0 kg/yr
0%
Septic Systems
69 kg/yr
69 kg/yr
0 kg/yr
0%
Agriculture
60 kg/yr
60 kg/yr
0 kg/yr
0%
Outflow from Canyon Lake
7,294 kg/yr
2,770 kg/yr
4,524 kg yr
62%
Total
55,876 kg/yr
28,584 kg/yr
1 27,292 kg/yr
49%
10 Source: Table 5 -9r on page 5 of 21 in Resolution No. R8- 2004 -0037. Note: allocations for internal sediment,
supplemental water, open /forest land, urban runoff, atmospheric deposition, septic systems and agriculture refer
only to the watershed area that drains directly to Lake Elsinore. Separate source allocations exist for these land -
use types where they flow to Lake Elsinore, indirectly, through Canyon Lake.
California Regional Water Quality Control Board - Santa Ana Region. Lake Elsinore and Canyon Lake Nutrient
TMDL Technical Report, 2004, pg. 74.
In -Lake Sediment Nutrient Reduction Plan for Lake Elsinore Page 7 of 30
Page 14 of 37
In order to restore the nutrient balance in Lake Elsinore, it will be necessary to reduce total
phosphorus loads by nearly 23,000 kg/yr. Reductions of such magnitude can only be achieved
by controlling contributions from the three largest sources of phosphorus: in -lake sediment
releases, reclaimed water discharges and in -flows from Canyon Lake. Remediation strategies
aimed at controlling the latter two sources are governed by Elsinore Valley MWD's NPDES
permit and other nutrient management plans specified in the Implementation Section of the
TMDL (see Table 6).
Table 6: Nutrient Management Plans for External Sources to Lake Elsinore
Source
TMDL
Description
Due Date
Status
Agriculture
Task #5
Agricultural Discharges -
Sept. 30, 2007
❑
Nutrient Management Plan
Septic
Task #6
On -site Disposal Systems -
Dependent on St.
❑
Systems
Management Plan
Bd. approval of
relevant regulations
Urban
Task #7
Revision of Drainage Area Mngt.
Aug. 1, 2006
Q
Runoff
Plan (DAMP) and Water Quality
Management Plan W MP
Forest Lands
Task #8
Forest Area Review /Revision of
Sept. 30, 2007
11
Forest Service Management Plans
Canyon Lake
Task #10
Canyon Lake In -Lake Sediment
May 31, 2007
Q
Pass -Thru
Treatment Evaluation
Most external nutrient loads are transported to the lake in the very wettest (aka "El Nino ") years
(see Table 7). Sustained heavy rains, like as those that occurred in 1993 and 1995, occur less
than 17% of the time but contribute nearly three - quarters of all new phosphorus loads to Lake
Elsinore. During the dry and moderate weather conditions that normally predominate in the
region, the vast majority of the San Jacinto watershed contributes virtually no flow or nutrient
loads to Lake Elsinore. 12 Rather, during dry and moderate years, most stormwater runoff is
retained in Mystic Lake and /or Canyon Lake before it reaches Lake Elsinore.
Given the immense flows that occur during El Nino, sometimes exceeding 500 efs in the San
Jacinto River channel, it is technically infeasible to divert the stormwater runoff. 13 In addition,
even if all external nutrient loads were eliminated entirely, water quality conditions in Lake
Elsinore would likely remain impaired for many decades, perhaps centuries. 14 Nevertheless, the
TMDL requires external loads to be reduced or offset in order to comply with relevant nutrient
targets and related water quality objectives.
12 Tetra Tech, Inc.; Lake Elsinore and Canyon Lake Nutrient Source Assessment Final Report. January, 2003; see
Tables 5 -5 thru 5 -13 on pgs. 5 -8 thru 5 -12.
13 Riverside County Flood Control and Water Conservation District. Canyon Lake, Lake Elsinore and San Jacinto
River Watershed Tour. Handout Packet dated Nov. 30, 2004.
MW H. Final Report: Engineering and Feasibility Study for NPDES Permit for Discharge to Lake Elsinore, Feb.,
2002. See pg. 4 -4.
In -Lake Sediment Nutrient Reduction Plan for Lake Elsinore Page 8 of 30
Page 15 of 37
Nutrient cycling from bottom sediments is now the dominant factor driving ambient water
quality conditions in the lake." Therefore, the most practical approach is to mitigate the adverse
effects of phosphorus after it reaches the lake but before it can impair the beneficial uses.
However, if this "offset approach" proves unsuccessful at meeting water quality objectives in
Lake Elsinore, additional controls to reduce external loads more directly may become necessary
to comply with the TMDL.
Table 7: Estimated External Phosphorus Loads to Lake Elsinore (1993 — 2004) 16
Rank
Year
External
Load
Percent of
12 -yr. Load
Cumulative
Percent
TMDL
Category
1
1993
99,487 kg
59%
59%
Wet
2
1995
22,257 kg
13%
72%
Wet
3
2004
9,897 kg
6%
78%
Moderate
4
1998
9,107 kg
5%
83%
Moderate
5
2003
8,593 k&
5%
88%
Moderate
6
2002
4,339 kg
3%
91%
Moderate
7
1997
3,816 kg
2%
93%
Moderate
8
1994
2,948 kg
2%
95%
Dry
9
1996
2,455 kg
1%
96%
Dry
10
2001
2,330 kg
1%
97%
Dry
11
1999
1,207 kg
l%
98%
Dry
12
2000
1,191 kg
1%
99%
Dry
3.0 In -Lake Nutrient Control Strategies
Historical records and data from sediment core samples indicate that phosphorous levels in Lake
Elsinore have been elevated for many centuries. 17 However, there is growing concern that
agricultural activities and urban development may cause these natural water quality conditions to
worsen.18 As a result, many studies have been performed to evaluate various nutrient reduction
strategies for the lake (see Table 8).
s Michael A. Anderson; Internal Loading and Nutrient Cycling in Lake Elsinore. August 31, 2001. See, also,
Anderson, Michael; Lake Elsinore Water Quality Model. 2003
16 M.A. Anderson; Predicted Effects of Restoration Efforts on Water Quality in Lake Elsinore: Model
Development and Results. March 12, 2006. See Table 4 on pg. 17.
17 Matthew E. Kirby, et al. Developing a Baseline of Natural Lake- Level/Hydrologic Variability and Understanding
Past versus Present Lake Productivity Over the Late - Holocene: A Paleo- Perspective for Management of Modern
Lake Elsinore. March, 2005.
18 California Regional Water Quality Control Board -Santa Ana Region. Problem Statement for Total Maximum
Daily Load for Nutrients in Lake Elsinore - Staff Report. 2001; See, also, U.S. Geological Survey. Effects of
Increased Urbanization from 1970's to 1990's on Storm -Runoff Characteristics in Perris Valley, California. Water -
Resources Investigations Report 95 -4273. 1996.
In -Lake Sediment Nutrient Reduction Plan for Lake Elsinore Page 9 of 30
Page 16 of 37
Table 8: Key Studies Used to Evaluate and Select Nutrient Reduction Strategies
Date
Report
Author(s)
1994
Lake Elsinore Water Quality Management Plan
Black & Veatch, Inc.
1994
Lake Elsinore Master Plan / Economic Feasibility Study: 1995 -2015
Noble Consultants, Inc.
1997
EVMWD: Lake Elsinore NPDES Permit Feasibility Study; Final
Phase 1 Technical Report
Montgomery Watson
Americas, Inc.
2000
Lake Elsinore Sediment -Water Interface Study Final Report
M. Bernet
2000
Laboratory and Limnocosm -Scale Evaluation of Restoration
Alternatives for Lake Elsinore. Final Report.
Dr. Michael A. Anderson
2001
Alum Application to Lake Elsinore: Responses to Questionnaire
Dr. G. Dennis Cooke
2001
Internal Loading and Nutrient Cycling in Lake Elsinore
Dr. Michael A. Anderson
2002
Rainfall - Runoff Characteristics and Effects of Increased Urban Density
on Streamflow and Infiltration in the Eastern Part of the San Jacinto
River Basin
U.S. Geological Survey
Water Resources
Report 02 -4090
2002
Proposed Lake Aeration and Biomanipulation for Lake Elsinore, CA
Arlo W. Fast
2002
Alum Application to Lake Elsinore: Questionnaire Update
Dr. G. Dennis Cooke
2002
Restoration of Canyon Lake and Benefits to Lake Elsinore Downstream
Dr. Alex J. Horne
2002
Impacts of Alum Addition on Water Quality in Lake Elsinore
Dr. Michael A. Anderson
2002
EVMWD: Engineering Feasibility Study for NPDES Permit for
Discharge to Lake Elsinore Final Report
Montgomery Watson
Harza, Inc.
2002
Lake Elsinore Replenishment Level Study Alternatives Analysis
Tetra Tech, Inc.
2002
Evaluation of Calcium Treatment for Control of Phosphorus in Lake
Elsinore
Dr. Michael A. Anderson
2002
Report on Evaluation of Potential Calcium Treatment to Enhance Water
Quality in Lake Elsinore
Dr. Ellie E. Prepas
2003
Lake Elsinore and Canyon Lake Nutrient Source Assessment
Tetra Tech, Inc.
2004
San Jacinto Nutrient Management Plan Final Report
Tetra Tech, Inc.
2004
Lake Elsinore Nutrient Removal Study
CH2M -Hill, Inc.
2004
Removal of Dissolved Phosphorus Using Calcium Amendment
Dr. Michael A. Anderson
2005
Developing a Baseline of Natural Lake -Level /Hydrologic Variability
and Understanding Past Versus Present Lake Productivity Over the
Late - Holocene: a Paleo- Perspective for Management of Modem Lake
Elsinore
Dr. Matthew E. Kirby
and
Dr. Michael A. Anderson
2005
Lake Elsinore Stabilization and Enhancement Project: Draft PEIR
MWH
2005
Final Fisheries Management Plan for Lake Elsinore
EIP Associates
2006
Predicted Effects of Restoration Efforts on Water Quality in Lake
Elsinore: Model Development and Results
Dr. Michael A. Anderson
2006
Feasibility Study Report: Nutrient Reduction Alternatives for Regional
Water Reclamation Facility Effluent Discharge to Lake Elsinore
MWH Americas, Inc.
2006
White Paper: Reasons for the TMDL Nitrogen Additional Studies of
Lake Elsinore in 2006 -07
Dr. Alex J. Horne
2007
Sediment Nutrient Flux and Oxygen Demand Study for Canyon Lake
with Assessment of In -Lake Alternatives
Dr. Michael A. Anderson
In -Lake Sediment Nutrient Reduction Plan for Lake Elsinore Page 10 of 30
Page 17 of 37
Some control strategies, such as large -scale dredging, were found to be impractical because it
would be necessary to remove 20 feet of sediment to have a significant effect on phosphorus
concentrations in the water column.'9 Other methods commonly used elsewhere to control algae,
such as applying liquid alum to bind with phosphorus and render it inert, are relatively
ineffective for Lake Elsinore due local water chemistry conditions (high pH) which are ill- suited
to such treatments except, perhaps, during short periods of time immediately following a storm
event 20
Relying on the large volume of technical reports prepared by interdisciplinary experts in lake
management, local stakeholders developed an innovative new approach for improving water
quality in Lake Elsinore. The approach, called "Biomanipulation," implements several
coordinated projects designed to reduce phosphorus loads from in -lake sediments. The three
primary mitigation strategies are: 1) a Lake Level Stabilization program, 2) an In -Lake Aeration
System, and 3) a Targeted Fisheries Management effort.
3.1 Lake Level Stabilization
Water levels in Lake Elsinore vary over a wide range (t18 ft.) due to natural fluctuations in
rainfall. During times of prolonged drought, such as occurred in the mid -50's and early 60's, the
lake nearly dried up altogether. As evaporation diminishes the volume of lake water,
conservative elements such as phosphorus become more concentrated. Elevated nutrient
concentrations, in turn, increase the risk of beneficial use impairment. Large changes in lake
elevation also make it very difficult to establish a stable riparian zone along the shoreline.
In 1995, a large levee was constructed to reduce the surface area of Lake Elsinore by nearly 50%
thereby minimizing the adverse effects of evaporation. However, by itself, even this drastic
reconfiguration is insufficient to provide the stable lake levels. Supplemental flow is provided
by several island wells which pump 3,000 acre -feet of groundwater into the lake each year.
In June of 2007, Elsinore Valley Municipal Water District (EVMWD) agreed to augment lake
levels by discharging high quality reclaimed water to Lake Elsinore. By stabilizing lake levels in
a range between 1240 -1248 feet above mean sea level, the supplemental water project will
establish the conditions necessary to promote more productive shoreline vegetation. The direct
and indirect environmental benefits of such bank habitat are numerous.
See Table 5 -2 on page 5 -4 of Montgomery- Watson's Final Report entitled:
NPDES Permit for Discharge to Lake Elsinore." February, 2002.
20 See, for example, G. Dennis Cooke. Alum Applications to Lake Elsinore.
Lake Elsinore Nutrient Removal Study. April, 2004
In -Lake Sediment Nutrient Reduction Plan for Lake Elsinore
"Engineering Feasibility Study for
2001 & 2002. See, also, CH2M -Hill.
Page 1 I of 30
Page 18 of 37
First, aquatic plants shield the underlying sediments from wind - driven waves and, thereby,
reduce the phosphorus releases that accompany resuspension. Second, the aquatic plants
themselves take up and sequester nutrients that would otherwise contribute to excess algae
growth. Third, the aquatic plants provide the type of habitat needed to support a stronger and
more diverse community of aquatic species (see Fig. B).
Fig. B: Biological Benefits of Lake Level Stabilization
increase
Bank Decrease
Vegetation Salinity
Reduce
Phosphorus Increase DO
Releases
In Sediment
In -Lake Sediment Nutrient Reduction Plan for Lake Elsinore Page 12 of 30
Page 19 of 37
The last point is especially important. Some aquatic organisms, such as zooplankton, feed on
algae thus helping to prevent beneficial use impairment. However, zooplankton reproduction is
inhibited at the higher salinity levels likely to occur as water evaporates from Lake Elsinore. By
providing supplemental flows of reclaimed water, Elsinore Valley MWD is stabilizing both the
lake level and the salinity concentration in a range that promotes a healthy zooplankton
population.
However, municipal effluent also contains elevated concentrations of nutrients such as nitrogen
and phosphorus (see Tables 4 & 5, above). Consequently, the TMDL requires EVMWD to
reduce nitrogen concentrations by 87% and phosphorus concentrations by 75% before the
reclaimed water can be discharged to Lake Elsinore. These obligations are set forth and
enforceable though a state and federal NPDES permit. In 2005, the Lake Elsinore and San
Jacinto Watersheds Authority (LESJWA) provided funding from the State of California Prop -13
Water Bond to contract with EVMWD to construct advanced waste treatment facilities, using
best available technology, to reduce nutrient concentrations in the effluent. Such treatment is
essential to support a long -term strategy for providing reclaimed water to stabilize the level of
Lake Elsinore.
Computer simulation studies, designed to model nutrient cycling processes in Lake Elsinore,
indicate that adding 4000 of /yr of highly treated reclaimed water will reduce the algae
concentrations by more than 50% and improve water clarity by nearly 100 %?' These estimates
are probably conservative because they are based solely on the expected benefit derived by
reducing wind and wave - driven sediment resuspension. Increased zooplankton populations and
enhanced shoreline vegetation are also expected to improve water clarity and reduce excessive
algae. At present, there is insufficient data to calibrate the nutrient models to estimate all of the
cause - effect relationships. However, on -going monitoring programs will be used to perform an
empirical analysis of these biological factors over the long -term.
3.2 In -Lake Aeration and Destratification
Dissolved oxygen levels in Lake Elsinore vary greatly by depth; concentrations range from less
than I mg /L near the bottom to over 11 mg /L near the surface. Low D.O. levels encourage
greater phosphorus releases from the sediment. The higher phosphorus concentrations stimulate
more algae growth which, in turn, consumes more oxygen especially during the nighttime hours.
Nutrient cycling is now the principle cause of water quality impairment in Lake Elsinore.
zi M.A. Anderson. Predicted Effects of Restoration Efforts on Water Quality in Lake Elsinore: Model
Development and Results. March 12, 2006.
In -Lake Sediment Nutrient Reduction Plan for Lake Elsinore Page 13 of 30
Page 20 of 37
LESJWA undertook an evaluation of the necessary aeration and oxygenation system for Lake
Elsinore and contracted with Dr. Arlo Fast to make appropriate recommendations. Dr. Fast's
report indicated that sufficient oxygen already exists but was not well distributed in the water
column. 22 He recommended a two phase mixing system to distribute and mix the oxygen
throughout the water column.
The first phase of the system consisted of axial flow water pumps. The system was implemented
in 2005 by the City of Lake Elsinore under contract with LESJWA with significant financial
support provided by California's Prop -I3 Water Bond .23 The pumps are designed to reduce
stratification by improving circulation in the lake. Forcing oxygen- saturated surface waters to
the bottom of the lake inhibits the anoxic conditions that promote higher phosphorus release rates
from the sediment.
The second phase consisted of a large -scale in -lake aeration system. 4 In June of 2007, LESJWA
provided Prop -I3 Water Bond funding to EVMWD to construct an in -lake aeration project is
designed to pump air through a system of twelve perforated pipelines submerged along the
bottom of Lake Elsinore (see Fig D). Like the axial pump, the aeration system improves
circulation so that oxygen levels are better distributed throughout the water column. The bubble
diffuser "lifts" oxygen - deficient bottom waters to the surface where it can be resaturated through
direct contact with the atmosphere.
The aeration pumps are only scheduled to operate during the warm- weather months when
oxygen levels are lowest, nutrient levels are highest, daylight hours are longest and algae growth
is greatest. Additional water quality benefits may accrue if the system is run more frequently;
however, it is considerably less efficient to operate outside the optimum range. Moreover, it may
be unnecessary.
Laboratory testing indicates that the in -lake aeration system will reduce the sediment release rate
for phosphorus by at least 35 %25 However, computer simulation studies suggest that a 35%
reduction in the sediment recycling rate may result in larger reductions for total phosphorus in
the water column — perhaps as much as 70% lower. 26 Figure C illustrates how the benefits are
expected to accrue.
22 Arlo W. Fast. Proposed Lake Aeration and Biomanipulation for Lake Elsinore, CA. 2002
z3 Agreement for the Operations and Maintenance of the Axial Flow Water Pump Destratification System for Lake
Elsinore. Feb. 11, 2003. Signatories: City of Lake Elsinore, Elsinore Valley Municipal Water District, & County
of Riverside.
24 Agreement for the Operation and Maintenance of the Lake Elsinore Phase 11 Aeration System. Aug. 1, 2006.
Signatories: City of Lake Elsinore, Elsinore Valley Municipal Water District, & County of Riverside.
21 Michael A. Anderson. Internal Loading and Nutrient Cycling in Lake Elsinore. Aug. 31, 2001.
26 M.A. Anderson. Predicted Effects of Restoration Efforts on Water Quality in Lake Elsinore: Model
Development and Results. March 12, 2006. p. 25
In -Lake Sediment Nutrient Reduction Plan for Lake Elsinore Page 14 of 30
Page 21 of 37
Fig. C: Biological Benefits of In -Lake Aeration
In-Lake Aeration
Destratify:
Increase
Circulation
Increase
DO
Reduce
Phosphorus
Releases in
Sediment
Reduce
Nutrients
in Water
Column
Feedback
Loop
Reduce
Algae
In -Lake Sediment Nutrient Reduction Plan for Lake Elsinore Page 15 of 30
Page 22 of 37
The Santa Ana Regional Water Quality Control Board assumed the in -lake aeration and mixing
systems would reduce phosphorus loads by 35% and included this assumption when formulating
the TMDL for Lake Elsinore?? The County of Riverside, the City of Lake Elsinore and Elsinore
Valley MWD have committed to continue operating the in -lake aeration and mixing systems
until mid -2011. Data from the first four years of operation will be used to determine the overall
effectiveness of the system. Based on this information, a new agreement will be negotiated
among the responsible parties identified in the TMDL to govern future operations of the system.
The new agreement will be submitted to the Santa Ana Regional Water Quality Control Board
for approval in December, 2010.
3.3 Targeted Fisheries Management
Some fish species, notably Carp and Shad, are seriously aggravating the nutrient problem in
Lake Elsinore. Carp forage for food in the sediment. This action, called "bioturbation,"
resuspends organic silt and thereby increases the amount of phosphorus released to the water
column by as much as 5,000 kg /yr (z 5% of the total load). Shad consume the zooplankton
species that would normally keep the algae population in check.
In order to improve water quality in Lake Elsinore, and provide better habitat or a wider range of
fish species, it is necessary to reduce the number of Carp and Shad significantly. This will be
accomplished by using direct and indirect methods (see Fig. D).
Direct methods are best exemplified by the City of Lake Elsinore's netting and stocking program.
Each year, LESJWA provides Prop -] 3 Water Bond funding to support a large -scale netting effort
designed to reduce the Carp population. The City also stocks the lake with sport fish (such as
Stripers) that feed on Carp and Shad and out - compete the nuisance species for available habitat.
Early indications are that these efforts have significantly reduced the number of both nuisance
species and, in turn, helped improve water quality in the lake despite the influx of new sediment
loads during the relatively wet winters of2005 and 2006. Prop -13 funding will end in 2010;
thereafter, local stakeholders must provide financial support for the program if it continues to
prove effective. If so, the responsible parties identified in the TMDL will negotiate a long -term
contract to extend the fishery management program (netting and stocking) and submit the
agreement to the Santa Ana Regional Water Quality Control Board by December, 2010.
s� California Regional Water Quality Control Board - Santa Ana Region. Lake Elsinore and Canyon Lake Nutrient
TMDL Technical Report. 2004.
In -Lake Sediment Nutrient Reduction Plan for Lake Elsinore Page 16 of 30
Page 23 of 37
Fig. D: Biological Benefits of Targeted Fisheries Management
Fisheries
Management
Netting Stocking
Reduce
Nutrients in
Water
Column
Reduce
Phosphorus
Releases in
Sediment
Feedback
Loop Reduce
Algae
increase DO
In -Lake Sediment Nutrient Reduction Plan for Lake Elsinore Page 17 of 30
Page 24 of 37
Indirect methods are best illustrated by EVMWD's flow augmentation program. Stabilizing the
lake level with reclaimed water will improve shoreline vegetation that provides habitat for
desirable zooplankton and fish species. In addition, the reclaimed water will help control salinity
concentrations in a range more favorable to the zooplankton. A large population of zooplankton
is essential to prevent excessive algae growth in Lake Elsinore.
Computer simulation studies indicate that reducing Carp populations by 50% will lower the
phosphorus loading rate by 5 mg /m2 /day (nearly 13%).28 Reducing the Carp population by 75%
will lower the phosphorus loading rate by 16 mg /m2 /day (32 %). At present, the simulation
models cannot quantify the benefits of increasing the zooplankton population by decreasing
water salinity and the number of Shad in Lake Elsinore. However, the long -term monitoring
program is designed to track such phenomena and the computer programs can be updated when
the data become available.
3.4 Compound Effects
The nutrient targets specified in the TMDL can be achieved by implementing several
remediation measures simultaneously. For example, installing the aeration system and reducing
the Carp population by 50% will decrease the phosphorus loading rate by 78 %.29 This estimate
is conservative because it assumes the total phosphorus concentration in recycled water is 2
mg /L rather than the 0.5 mg/L allowed by permit. In addition, it does not include the expected
benefits derived from higher lake levels or larger zooplankton populations.
Biomanipulation is a complex implementation strategy with many inter- related cause and effect
relationships. The cumulative beneficial impact of this integrated remediation effort is actually
greater than the sum of the individual interventions.
Ultimately, compliance must be assessed using actual water quality monitoring data not the
results of sophisticated computer simulations. And, such a monitoring program is already
underway. Nevertheless, analysis -to -date indicates that the on -going biomanipulation strategy
will restore water quality in Lake Elsinore to better than natural background conditions.
28 M.A. Anderson. Predicted Effects of Restoration Efforts on Water Quality in Lake Elsinore: Model
Development and Results. March 12, 2006. p. 25
29 M.A. Anderson. Predicted Effects of Restoration Efforts on Water Quality in Lake Elsinore: Model
Development and Results. March 12, 2006. p. 25
In -Lake Sediment Nutrient Reduction Plan for Lake Elsinore Page 18 of 30
Page 25 of 37
4.0 Compliance Monitoring
The monitoring program proposed for Lake Elsinore is not merely designed to demonstrate
compliance with the numeric nutrient targets identified in the TMDL but, also, to show that the
beneficial uses themselves are being attained. To that end, many different parameters are
evaluated simultaneously to better assess the health of Lake Elsinore's aquatic ecosystem.
4.1 Water Quality Monitoring
The most direct method of establishing compliance with water quality objectives in the Basin
Plan is to collect and analyze water samples on a regular basis. The TMDL requires samples to
be collected from at least three stations in Lake Elsinore. The samples are to be collected
monthly between October and May and biweekly in the months of June through September. 30 In
addition to other parameters, samples are analyzed for all of constituents listed in Table 9.
Table 9: In -Lake Water Quality Monitoring Program for Lake Elsinore
Category
Parameter
Oxygen
Dissolved Oxygen*
Chemical Oxygen Demand COD
Biolo ical Ox en Demand BOD
Water
Clarity
Secchi Depth
Turbidity
Total Suspended Solids TSS
Chlorophyll a*
Nutrients
Ortho- hos hate (SRP)*
Organic Phosphorus*
Organic Nitrogen*
Nitrite Nitrogen*
Nitrate Nitro en*
Ammonia Nitro en*
Salinity
Total Dissolved Solids TDS
Specific Conductance
Total Hardness
Physical
H
WaterTemperature
*Indicates a parameter that must meet specific numeric targets identified in the TMDL. Nutrient
parameters are summed into Total Phosphorus and Total Nitrogen.
J0 A more detailed description is provided in the Proposed Lake Elsinore and Canyon Lake Nutrient TMDL
Monitoring Plan (Feb. 15, 2006) approved by the Regional Board on March 3, 2006 as Resolution No. 88 -2006-
0031.
In -Lake Sediment Nutrient Reduction Plan for Lake Elsinore Page 19 of 30
Page 26 of 37
Results from the water quality monitoring program will be compared to the numeric targets
identified in the TMDL, using the methods and procedures specified in the State Water
Resources Control Board's 303(d) listing policy. 31 In addition, the data may be used to update
and revise the various computer simulation models used to predict changes in water quality in
Lake Elsinore.
4.2 Biological Monitoring
The primary purpose of improving water quality in Lake Elsinore is to protect aquatic organisms.
Although one may infer that lower nutrient concentrations and high DO levels are beneficial to
fish and other species living in the lake, it is desirable to demonstrate such improvements more
directly. This is especially important when implementing strategies designed to mitigate the
adverse effects of pollution rather than relying, exclusively, on pollution reduction programs.
For example, it may be more efficient and effective to control algae by stimulating the
zooplankton population than it is to reduce phosphorus concentrations. The In -Lake Nutrient
Reduction Plan for Lake Elsinore intends to pursue both of these strategies in addition to several
other compliance initiatives. And, as a result, it is likely that beneficial uses will be protected
(e.g. response targets will be attained) even if nutrient targets are not always met.
Some response variables, such as D.O. and Chlorophyll -a, are already included among the
parameters that must be evaluated as part of the regular water quality monitoring program.
Compliance with these TMDL targets would form the primary basis for assessing beneficial use
protection . However, there are other indicators of biological integrity which should also be
considered (see Table 10). A plan to expand the current monitoring program to include
additional biological monitoring will be submitted to the Regional Board by June of 2008.
Table 10: Recommended Biological Monitoring Program for Lake Elsinore
Parameter
Frequency
Fish Richness and Abundance
Annually
Zooplankton Abundance
Annually
Algae Richness and Abundance
Annually
Shoreline Vegetation Survey
Bi- annually
Aquatic Plant Survey
Bi- annually
31 California State Water Resources Control Board. Water Quality Control Policy for Developing California's Clean
Water Act Section 303(d) List. September 30, 2004.
In -Lake Sediment Nutrient Reduction Plan for Lake Elsinore Page 20 of 30
Page 27 of 37
Results from the biological monitoring program will be used to recalibrate the computer
simulation models used to predict changes in DO or algae concentrations based on changes in
nutrient levels while controlling for other important variables such as the size of various fish and
plant populations. Ultimately, as water quality improves, biological monitoring data may be
used to demonstrate that DO and algae levels are better than would occur under natural
conditions and that beneficial uses in Lake Elsinore are no longer impaired. In addition, results
from the biological monitoring program will be invaluable for developing "biocriteria," an
essential element of TMDL Task # 13 (Reviewing and Revising Nutrient Water Quality
Objectives."
Table 11: Water Quality Monitoring Reports for Lake Elsinore
In -Lake Sediment Nutrient Reduction Plan for Lake Elsinore Page 21 of 30
Page 28 of 37
Title of Monitoring Report
1
Water Quality Report for Lake Elsinore & Evaluation Program -3`d Quarter, 2002
2
Water Quality Report for Lake Elsinore & Evaluation Program4h Quarter, 2002
3
Water Quality Report for Lake Elsinore & Evaluation Program -1 s` Quarter, 2003
4
Water Quality Report for Lake Elsinore & Evaluation Program -2 "d Quarter, 2003
5
Water Quality Report for Lake Elsinore & Evaluation Pro ram -3rd Quarter, 2003
6
Water Quality Report for Lake Elsinore & Evaluation Program -4`' Quarter, 2003
7
Water Quality Report for Lake Elsinore & Evaluation Program -15t Quarter, 2004
8
1 Water Quality Report for Lake Elsinore & Evaluation Program -2nd Quarter, 2004
9
Water Quality Report for Lake Elsinore & Evaluation Program -3`d Quarter, 2004
10
Water Quality Report for Lake Elsinore & Evaluation Program4h Quarter, 2004
11
Water Quality Report for Lake Elsinore & Evaluation Program -Is` Quarter, 2005
12
Water Quality Report for Lake Elsinore & Evaluation Program -2 "d Quarter, 2005
13
Water Quality Report for Lake Elsinore & Evaluation Program -3`d Quarter, 2005
14
Water Quality Report for Lake Elsinore & Evaluation Program-4 Quarter, 2005
15
1 Water Quality Report for Lake Elsinore & Evaluation Program -l'` Quarter, 2006
16
Water Quality Report for Lake Elsinore & Evaluation Program -2 "d Quarter, 2006
17
Water Quality Report for Lake Elsinore & Evaluation Program -3`d Quarter, 2006
18
Water Quality Report for Lake Elsinore & Evaluation Program -4`h Quarter, 2006
19
Water Quality Report for Lake Elsinore & Evaluation Program -15 Quarter, 2007
20
Water Quality Report for Lake Elsinore & Evaluation Program -2 "d Quarter, 2007
21
Water Quality Report for Lake Elsinore & Evaluation Program -3`d Quarter, 2007
In -Lake Sediment Nutrient Reduction Plan for Lake Elsinore Page 21 of 30
Page 28 of 37
4.3 Special Studies
Although the TMDL does not require the In -Lake Sediment Nutrient Reduction Plan to meet
specific load allocations for total nitrogen, the Regional Board staff has indicated that some
nitrogen- reduction benefits were expected to occur when the aeration system is installed.
Therefore, some special studies have been initiated to provide additional scientific
confirmation. 32 These include:
1) In -lake measurements of the sediment organisms as a living sink for
Nitrogen.
2) Estimation of sediment denitrification as an atmospheric sink for Nitrogen.
3) In -lake samples of the nitrogen fixing potential of the lake as a source for
Nitrogen.
EVMWD contracted with Dr. Alex Horne to perform the studies and initial samples were
collected in September, 2006. Additional sampling is expected to be conducted in the Fall of
2007. Results will be reported to the Regional Board.
4.4 Water Quality Modeling
All of the additional monitoring data described above is a necessary prerequisite to completing
TMDL Task #11: Updating the Lake Elsinore In -Lake Water Quality Model 33 Until the
aeration system comes on -line, and new data are collected, there is little value in running the
current water quality models for Lake Elsinore. Therefore, the Regional Board has extended the
deadline to March of 2009 in order to collect additional chemical and biological data. 34
3z Alex J. Horne. White Paper: Reasons for the TMDL Nitrogen Additional Studies of Lake Elsinore in 2006.07.
August 14, 2006.
" Source: Table 5 -9s on pg. 7 of 21 in R8- 2004 -0037.
34 California Regional Water Quality Control Board - Santa Ana Region. Letter to Mr. Mark Norton, Lake Elsinore
& San Jacinto Watersheds Authority dated April 30, 2007.
In -Lake Sediment Nutrient Reduction Plan for Lake Elsinore Page 22 of 30
Page 29 of 37
5.0 Supplemental Control Strategies
The biomanipulation program described in Section 3 is expected to achieve compliance with the
chemical and biological targets specified in the TMDL. However, in the event the proposed
program proves inadequate, there may be additional options to further reduce nutrient loads
released from in -lake sediments. These include:
5.1) An Enhanced Aeration System
The software code used to control the existing aeration system can be revised to operate the
aerators more frequently (more months of the year, more days of the month, or more hours in a
day). In addition, additional pipelines and /or aerators may be installed to provide better
coverage. The utility of this option depends on the demonstrated effectiveness of the current
aeration system and the related oxygenation efficiency curve of additional aeration.
5.2) Enhanced Treatment of Reclaimed Water
EVMWD's NPDES permit limits phosphorus concentrations in reclaimed water discharged to
Lake Elsinore to less than 0.5 mg /L. Additional alum application at the wastewater treatment
plant may reduce nutrient concentrations even further. This may provide any opportunity to
offset non -point source loads by engaging in pollutant trading with point sources.
5.3) Direct Application of Metal Salts
Alum and other metal salts are frequently used to reduce phosphorus concentrations in small
lakes. In general, Lake Elsinore is poorly suited for the use of alum because the relatively high
pH levels inhibit the intended formation of aluminum phosphate. 35 However, under certain
conditions, pH levels may be low enough to support the application of metal salts, such as alum,
to Lake Elsinore.
In very wet years, when the inflows to Lake Elsinore are greatest, pH levels tend to decrease.
This is not surprising because the pH of rain water is naturally low. If large scale alum
applications were timed to coincide with wet winters, much of the new dissolved phosphorus
flowing into the lake might be neutralized. Another option may be to apply alum to Canyon
Lake and reduce the phosphorus concentrations before the water overflows into Lake Elsinore. 36
3s Michael A. Anderson. Impacts of Alum Addition on Water Quality in Lake Elsinore. Feb. 1, 2002.
3' These and other alternatives are described in CH2M- Hill's report entitled: Lake Elsinore Nutrient Removal Study.
April, 2004.
In -Lake Sediment Nutrient Reduction Plan for Lake Elsinore Page 23 of 30
Page 30 of 37
5.4 Targeted Suction Dredging
Previous studies indicate a disproportionate amount of phosphorus released from in -lake
sediments is coming from the organic silt layer in the middle of the lake 37 And, preliminary
reports suggest that most of the phosphorus is coming from the top 15 cm of sediment.
Therefore, limited suction dredging, targeting the top 6 inches of sediment in the middle of the
take may prove to be an effective mitigation strategy.
5.5 Constructed Wetlands
LESJWA is currently developing a pilot project to demonstrate the effectiveness of constructed
wetlands for reducing nutrient concentrations in Lake Elsinore. Theoretically, stormwater runoff
could be diverted through such wetlands for treatment prior to entering the lake. Alternatively,
lake water could be pumped up and flow through the wetlands during drier years. When the
levee was constructed, and the surface area of Lake Elsinore was cut in half, a large back -basin
area was created that may serve as an ideal location to build treatment wetlands. Data from the
pilot project will help determine whether such an approach would be practical on a larger scale.
5.6 Active Aquatic Plant Management
Over time, stabilizing the lake level and reducing the algae infestation will provide an
opportunity for native aquatic plants to recolonize the lake. It may also be possible to accelerate
the process by initiating a program to actively revegetate the shoreline and the lake bottom.
Aquatic plants will serve as a natural sink for nutrients, will provide better habitat for beneficial
freshwater species, and reduce the level of sediment resuspension caused by wind and wave
action.
5.7 Enhanced Fishery Management Program
The City of Lake Elsinore has demonstrated the general effectiveness of actively managing the
fish populations through netting and stocking programs. Such programs, particularly stocking
efforts, could be significantly expanded if there were a way to calculate and credit the nutrient -
removal credit associated with such an effort. Data collected from the water quality monitoring
program may provide the information needed to validate the beneficial use protection value and,
thereby, create an incentive to augment the City's fishery management program.
}� California Regional Water Quality Control Board - Santa Ana Region. Lake Elsinore and Canyon Lake Nutrient
TMDL Technical Report; 2004 @ pgs. 29 -31.
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5.8 Enhanced Lake Stabilization
Previous studies revealed that 13- 15,000 acre -feet of water evaporates each year from Lake
Elsinore. 38 On average, only about 1,400 acre -feet flows into Lake Elsinore annually. The
island wells provide an additional 3,000 acre -feet of groundwater and reclaimed water adds
5,000 acre -feet of supplemental flow each year. Therefore, more water (up to 5,000 acre -
feet /year) may be needed to fully offset evaporative losses and stabilize the lake level in the ideal
range. The most cost - effective and reliable source is high quality reclaimed water from local
wastewater plants. However, additional treatment would be necessary to reduce nutrient
concentrations to acceptable levels before more reclaimed water could be added to Lake
Elsinore. And, the cost of such treatment would have to be heavily subsidized by the responsible
parties named in the TMDL.
5.9 Pollutant Trading
Many of the supplemental control strategies seek to restore and protect beneficial uses through
indirect means. Consequently, it is necessary to develop a system which can accurately assess
the benefits and correctly credit those responsible for implementing these strategies. In fact,
Task 12 of the TMDL envisions creating just such a system. 39
The TMDL requires stormwater management agencies to employ Best Management Practices to
minimize pollutants in urban runoff. However, as a practical matter, it may be infeasible to
divert or treat the immense volume of urban runoff flowing to Lake Elsinore during wet years.
Therefore, another way to comply with external load reductions mandated in the TMDL is to
mitigate the negative effects after the nutrients enter Lake Elsinore but before the pollutants
begin to impair beneficial uses.
This condition creates a strong economic incentive for the parties responsible for achieving
external load reductions to fund offset programs designed to reduce internal nutrient loads. For
example, if an appropriate credit can be affirmed by the Regional Board, it may be more cost -
effective for stakeholders to operate the aerators more frequently, or apply alum intermittently,
or dredge selectively then to build the infrastructure necessary to intercept urban or agricultural
runoff to Lake Elsinore. Other nutrient offset programs may be available if a stakeholder were
willing to fund additional efforts to reduce phosphorus concentrations in EVMWD's reclaimed
water before it is discharged to Lake Elsinore.
3s See Section 3 in CH2MHill's "Lake Elsinore Nutrient Removal Study;" April, 2004.
Source: Table 5 -9s on pg. 7 of 21 in R8- 2004 -0037.
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The utility of a pollutant trading program depends on three things: 1) the need to further reduce
nutrient concentrations in order to comply with the TMDL; 2) the availability of a cost - effective
offset opportunity; and 3) regulatory acceptance of the offset trade as an alternative means of
demonstrating legal compliance. Data from the on -going monitoring program will be needed to
support all three. Therefore, the Regional Board has extended the deadline for submitting a
Pollutant Trading Plan until Spring of 2009 so that the necessary information may be collected.
5.10 Other Alternatives
Previous reports have suggested other alternatives that may also be reevaluated in the future.
These include: dredging, algae harvesting, sediment sealing, dye shading, dilution /flushing,
selective withdrawal of low DO waters from lake bottom, ete.40
6.0 Implementation Schedule
The In -Lake Sediment Nutrient Reduction Plan for Lake Elsinore is divided into two phases.
Phase 1, to stabilize lake levels, install aerators and initiate a fishery management strategy, is
well underway. If, as expected, Phase 1 is successful, then there is no need to develop Phase 2
implementation strategies. There will, however, be a need to ensure that the previous projects
continue to operate effectively.
If the monitoring program demonstrates that Phase 1 efforts fail to meet the targets identified in
the TMDL, then a Phase 2 implementation strategy will be required. Phase 2 will likely focus on
one or more of the Supplemental Control Strategies described in Section 5. However, it is not
possible to predict, with any certainty, the order in which these strategies might be implemented.
Too much depends on the monitoring results from Phase 1 and the related modeling predictions.
The load allocations and wasteload allocations specified in the TMDL, are expressed and 10 -year
rolling averages and compliance with final targets is required by the year 2020. Compliance
with the 10 -year rolling average will be determined beginning with water quality data collected
in 2011. In addition, responsible parties must demonstrate compliance with the interim targets
for some of the response variables (e.g. DO & Chlorophyll -A) by 2015. Therefore, stakeholders
must make a decision by 2010 as to whether additional efforts will be needed to meet the TMDL
targets on schedule. Tablc 12 provides a inure detailed schedule to guide both Phase I and 2.
40 See, for example, Table 5 -2 on page 5 -4 of report prepared by Montgomery- Watson entitled 'Engineering
Feasibility Study for NPDES Permit for Discharge to Lake Elsinore." February, 2002.
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Table 12: Schedule for Lake Elsinore In -Lake Sediment Nutrient Reduction Plan
Phase
Task Description
Deadline
1
Install Aeration & Axial Flow Pump Mixing Systems
Complete
1
Supplemental Reclaimed Water Flows
Complete
1
Submit Preliminary Plan to Update Water Quality Models*
Complete
1
Submit Preliminary Pollutant Trading Plan*
Complete
1
Revise and Update WDRs and MS4 Permits
Mar., 2008
1
Revise Monitoring Plan to include Biological Sampling Program
June, 2008
I
Summarize Results of Monitoring Program
Aug., 2008
1 1
Summarize Results of Monitoring Program
Aug., 2009
1
First TMDL Review
Nov., 2009
1
Review Nutrient Water Quality Objectives
Mar., 2010
1
Summarize Results of Monitoring Program
Aug., 2010
1
Update Water Quality Models
Nov., 2010
1
Submit O & M Agreement for Fishery Management Program
Dec., 2010
1
Submit O & M Agreement for Aeration & Mixing Systems
Dec., 2010
1
Submit Phase 2 Implementation Alternatives
Dec., 2010
2
Begin data collection to calculate l0- ear rolling average
Jan., 2011
2
Submit Phase 2 Projects Plan
June, 2011
2
Summarize Results of Monitoring Program
Aug., 2011
2
Second TMDL Review
Nov., 2012
2
Revise & Update WDRs and MS4 Permits
Mar., 2013
2
Summarize Results of Monitoring Program
Aug., 2013
2
Summarize Results of Monitoring Program
Aug., 2014
2
Com lete Phase 2 Project Implementation
Dec., 2014
2
Summarize Results of Monitoring Program
Aug., 2015
2
Third TMDL Review
Nov., 2015
2
Compliance Deadline for Interim Targets (DO & Chlorophyll-4)
ec., 2015
2
Summarize Results of Monitoring Program
Auiz., 2016
2
Summarize Results of Monitoring Program
Aug., 2017
2
Revise and Update WDRs & MS4 Permits
Mar., 2018
2
Summarize Results of Monitoring Program
Aug., 2018
2
Fourth TMDL Review
Nov., 2018
2
Summarize Results of Monitoring Program
Aug., 2019
2
Summarize Results of Monitoring Program
-Aug., 2020
2
Compliance Deadline for 10-year Rolling Averages (N, P, NO3 )
Dec., 2020
2
Final TMDL Review (De-Listing Petition
Dec., 2021
*More detailed schedules to complete Updates to the Watershed and In -Lake Nutrient Models (TMDL Task # 11)
and the Pollutant Trading Program (TMDL Task # 12) were submitted to the Regional Board in separate plans as
required by Resolution No. R8- 2004 -0037.
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7.0 Summary
Lake Elsinore is a dynamic and complex ecosystem. Manipulating several chemical and
biological variables simultaneously to improve water quality and restore beneficial uses is an
ambitious and somewhat daunting task.
It is unlikely that the stakeholders will implement the perfect solution on the first try. Rather,
success will depend on an iterative process of developing mitigation projects, measuring results,
updating the predictive models and refine the follow -on strategy. This process of "adaptive
implementation" makes best use of scarce public resources and reduces the risk of unforeseen
consequences by emphasizing incremental changes.
Fig. E: Adaptive Management to Protect Lake Elsinore
Motlify Mitigation
Requirements Strategies
Modeling Monitoring
Predictions Progress 001
Using the lake as a laboratory, successful projects can be repeated or expanded. Unsuccessful
projects can be terminated and resources shifted to alternative approaches. Moreover, as
additional data becomes available, the ability to accurately assess the lake's true potential, and
the steps necessary to achieve that potential, will also improve.
In -Lake Sediment Nutrient Reduction Plan for Lake Elsinore Page 28 of 30
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By adopting the TMDL, and the related load allocations and wasteload allocations, the Santa
Ana Regional Water Quality Control Board established a baseline set of expectations about the
actions needed to meet the water quality objectives for Lake Elsinore. It will be necessary to
reduce nutrient loads from both internal and external sources in order to comply with the TMDL.
The multi - pronged approach initiated in Phase 1 (e.g. lake stabilization, aeration /mixing, and
fishery management) is expected to achieve the necessary internal load reductions.
Implementing Best Management Practices (BMPs) as the watershed is developed is expected to
reduce external loads sufficiently. However, some nutrient loading to Lake Elsinore comes from
natural sources that cannot be easily controlled and responsibility cannot be easily assigned.
Therefore, it is useful to maintain a high level of flexibility to reallocate loads between point and
non -point sources, to raise or lower water quality objectives, and to modify TMDL targets as
necessary to ensure that beneficial uses are protected. The true end -goal is to prevent fish kills
and excessive algae growth that interferes with recreational opportunities (see Table 13).
Table 13: Hierarchy of Use Impairment Indicators
Use Impairment
Aquatic Organisms
Human Recreation
Level 1 Indicator
Significant Fish Kills
Significant Illness
Level 2 Indicator
Species Richness & Abundance
User Acceptance
Level 3 Indicator
Un- ionized Ammonia & DO
Aesthetic Conditions
Level 4 Indicator
Algae Concentrations
Algae Concentrations
Level 5 Indicator
Nutrient Concentrations
Nutrient Concentrations
Achieving specific nutrient concentrations is a means to an end, not an end in itself. Success will
be measured as much by increased public enjoyment of the lake and by greater richness and
abundance of aquatic organisms as by chemical analyses. Adaptive management is designed to
achieve those goals. Biological and chemical monitoring results will be reviewed annually and
the TMDL targets and allocations will be reviewed every three years to maintain that "real -
world" focus (see Fig. F).
In -Lake Sediment Nutrient Reduction Plan for Lake Elsinore Page 29 of 30
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Fig. F: TMDL Review Process
' Response `
Targets?
(DO, Ammonia,
Algae) ,
Nutrient
Targets?
Not
Increase
Delist the Reasses TMDL
Waterbody Targets 8
Allocations
Note: Response variables are "attained" when fish kills
and algae infestation are less than they would otherwise be,
and DO concentrations are better than they would otherwise
be, under natural, non - urbanized, nomagricuitural conditions.
M.E.P. _ "Maximum Extent Practicable"
SMPs
3mMttet
In -Lake Sediment Nutrient Reduction Plan for Lake Elsinore
Nutrient
Targets?
Wate r a i
Water r Q Duallitly y
Standards
Reduce
TMDL
Targets &
Allocations
Anthropogenic
Source?
Regulatory
Action
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