July 22, 2014 Santa Ana Watershed Project Authority Attn: Mark Norton, Water Resources & Planning Manager 11615 Sterling Avenue Riverside, CA 92503 Subject: Proposal to Investigate and Characterize the Cause(s) of Recent Exceedances of the TDS Objective for Reach 3 of the Santa Ana River Dear Mr. Norton: Pursuant to a request by the Basin Monitoring Program Task Force (Task Force), Wildermuth Environmental Inc. (WEI) has prepared this proposal to investigate and characterize the cause(s) of recent exceedances of the total dissolved solids (TDS) objective for Reach 3 of the Santa Ana River (SAR). The estimated cost to perform this investigation is about $34,400, which includes an optional task to document the findings of the investigation in a technical memorandum. The investigation methodology, scope of work, schedule and budget are described below. Background The three primary components of stream discharge (flow) in the SAR at Prado Dam are: storm flow, non- tributary flow, and base flow. Storm flow is rainfall runoff. Non-tributary flow typically originates from outside the watershed (imported water) or is an episodic transfer of water within the watershed. Base flow is the remainder, and mainly includes POTW discharge, rising groundwater, and dry-weather runoff. The Regional Board has established a TDS objective of 700 mg/L for the base flow of the SAR at Prado Dam—the so-called Reach 3 objective. The purpose of the objective is to protect the beneficial uses of the SAR in the Orange County management zone—the primary use being groundwater recharge. To measure compliance with this objective the Regional Board coordinates a program to collect and analyze grab samples of the SAR at the USGS gaging station at Below Prado Dam during the summertime months of August and September—a time when the influences of storm flow and non-tributary flow typically is at a minimum. The Regional Board also uses the data from this program (and other monitoring programs) to evaluate the efficacy of its current regulatory approach, such as the wasteload allocation. Recent data from this program indicate that the TDS concentration of the SAR base flow has been increasing, and in some recent instances has exceeded the TDS objective for Reach 3 of 700 mg/L. Recent modeling results performed for establishing the wasteload allocation for the SAR did not predict these exceedances. For these reasons, the Regional Board and the Orange County Water District have
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July 22, 2014 Santa Ana Watershed Project Authority Attn: Mark Norton, Water Resources & Planning Manager 11615 Sterling Avenue Riverside, CA 92503 Subject: Proposal to Investigate and Characterize the Cause(s) of Recent Exceedances of the TDS
Objective for Reach 3 of the Santa Ana River Dear Mr. Norton: Pursuant to a request by the Basin Monitoring Program Task Force (Task Force), Wildermuth Environmental Inc. (WEI) has prepared this proposal to investigate and characterize the cause(s) of recent exceedances of the total dissolved solids (TDS) objective for Reach 3 of the Santa Ana River (SAR). The estimated cost to perform this investigation is about $34,400, which includes an optional task to document the findings of the investigation in a technical memorandum. The investigation methodology, scope of work, schedule and budget are described below.
Background
The three primary components of stream discharge (flow) in the SAR at Prado Dam are: storm flow, non-tributary flow, and base flow. Storm flow is rainfall runoff. Non-tributary flow typically originates from outside the watershed (imported water) or is an episodic transfer of water within the watershed. Base flow is the remainder, and mainly includes POTW discharge, rising groundwater, and dry-weather runoff.
The Regional Board has established a TDS objective of 700 mg/L for the base flow of the SAR at Prado Dam—the so-called Reach 3 objective. The purpose of the objective is to protect the beneficial uses of the SAR in the Orange County management zone—the primary use being groundwater recharge. To measure compliance with this objective the Regional Board coordinates a program to collect and analyze grab samples of the SAR at the USGS gaging station at Below Prado Dam during the summertime months of August and September—a time when the influences of storm flow and non-tributary flow typically is at a minimum. The Regional Board also uses the data from this program (and other monitoring programs) to evaluate the efficacy of its current regulatory approach, such as the wasteload allocation.
Recent data from this program indicate that the TDS concentration of the SAR base flow has been increasing, and in some recent instances has exceeded the TDS objective for Reach 3 of 700 mg/L. Recent modeling results performed for establishing the wasteload allocation for the SAR did not predict these exceedances. For these reasons, the Regional Board and the Orange County Water District have
Mr. Mark Norton July 22, 2014 Re: Investigate and Characterize the Cause(s) of Recent TDS Exceedances … Page 2 of 4
requested an investigation of the cause(s) of the recent exceedances of the TDS objective for Reach 3 of the SAR.
Methodology
The volume and TDS concentration of most major components of base flow and non-tributary discharge in the SAR at Prado Dam are known (e.g. POTW discharge). For the period 2004-2012, the Chino Basin Watermaster (CBWM) and the Inland Empire Utilities Agency (IEUA) collected and compiled monitoring data from surface-water monitoring locations and POTW discharge locations upstream from Prado Dam and at Below Prado as part of the Chino Basin Hydraulic Control Monitoring Program (HCMP). These data will form the basis for the investigation.
Storm flow during the summertime is typically minimal. There are other unmeasured inflows and outflows to the SAR above Prado Dam that are not precisely known, including net rising groundwater. Herein, we call these collective unknowns the “Residual” flow. Using the known volumes and TDS concentrations of the components of summertime flow in the SAR, a set of mass balance equations will be used to calculate the volume and TDS concentration of the Residual:
QP = (QCC – QOC) + QRP1 + QMC + QW + QRR + QTC +QC1B – ET + RQ
QP*CP = [(QCC*CCC) – (QOC*COC) + (QRP1*CRP1) + (QMC*CMC) + (QW*CW) + (QRR*CRR ) + (QTC*CTC ) + (QC1B*CC1B)+ (RQ*RC)
Where,
Q = flow C = TDS concentration ET = evapotranspiration RQ = calculated Residual flow RC = calculated TDS concentration of Residual flow and the subscripts refer to the surface-water monitoring locations,
P = SAR at Below Prado Dam CC = Chino Creek at Pine Ave OC = OC-59 (imported water discharge location) MC = Mill Creek at Chino RR = SAR at River Road TC = Temescal Creek above Main Street in Corona
and the POTW discharge locations downstream of the surface-water monitoring locations,
RP1 = IEUA RP1 at Prado W = Western Riverside County Regional Wastewater Treatment Plant C1B = City of Corona Plant 1B
This time history of mass balance will be analyzed, and the mass-balance factors will be manipulated in a prospective manner, to characterize the relative influence of each component of base flow on the TDS concentration of the SAR at Below Prado (including the Residual).
Mr. Mark Norton July 22, 2014 Re: Investigate and Characterize the Cause(s) of Recent TDS Exceedances … Page 3 of 4
Scope of Work
Task 1: Identify the Source(s) of TDS Exceedances at Prado
The purpose of this task is to identify the cause(s) of the recent exceedances of the TDS objective for Reach 3 of the SAR, to characterize their relative influence, and to present the conclusions to the Task Force.
The work includes the following subtasks:
Task 1.1 – Assemble Discharge and TDS Concentration from the HCMP. Much of this data for the period 2004-2012 have already been collected, checked, and uploaded into HydroDaVESM as part of the HCMP. The purpose of this subtask is to collect, extract, and prepare data for analysis.
Task 1.2 – Develop Discharge and TDS Mass Balance and Estimate Residual Discharge/TDS Terms. The purpose of this subtask to develop and solve the discharge and TDS mass-balance equations using the data prepared in Task 1.1.
Task 1.3 – Review Mass Balance Tables and Develop Preliminary Conclusions of the Cause of TDS Exceedance; Prepare Excel Workbook for the Task Force. The purpose of the subtask is to analyze the information developed in Task 1.2 and identify and characterize the cause(s) of the exceedances of the TDS objective for Reach 3 of the SAR.
Task 1.4 – Prepare PowerPoint Presentation and Meet with Task Force to Present and Discuss Preliminary Conclusions. The purpose of this subtask is to prepare for and give a presentation to the Task Force summarizing the analysis and conclusions of the investigation. The presentation will include handouts of the draft tables and figures developed during the analysis.
Task 1.5 – Revise Discharge and TDS Mass Balance Estimates Based on Task Force Comments and Finalize Conclusions. The purpose of this subtask is to finalize the mass-balance analysis and conclusions based on comments provided by the Task Force. A final version of the figures and tables provided in Task 1.4 will be submitted electronically to the Task Force.
Task 2: Prepare Technical Memorandum (Optional)
The purpose of this optional task is to prepare a letter report for the Task Force that describes the methods, results, conclusions and recommendations of this work. The letter report will include the tables and figures developed in Task 1. WEI will prepare a draft technical memorandum and submit it to the Task Force for review and comment. A final report will be submitted to the Task Force after comments have been addressed. The estimated cost to complete Task 2 is $7,780 and assumes the letter report will be submitted as an electronic deliverable.
Budget and Schedule
Task 1 can be completed within four weeks of a notice to proceed. The Task 2 draft letter report can be completed within four weeks of presenting the conclusions of Task 1 to the Task Force. The total cost to complete Tasks 1 and 2 is about $34,400. The cost to complete Task 1 only is about $26,600 (if the Task Force does not request the documentation of Task 2).
Mr. Mark Norton July 22, 2014 Re: Investigate and Characterize the Cause(s) of Recent TDS Exceedances … Page 4 of 4
We can begin executing this scope of work immediately. We appreciate the opportunity to serve the Task Force. Please call me or Andy Malone if you have any questions or need further assistance. Very truly yours, Wildermuth Environmental, Inc.
Mark Wildermuth, PE Andy Malone, PG President, Principal Engineer Principal Geologist
$26,520 $121 $26,641
1.1 Assemble discharge and TDS concentration data from the CBWM/IEUA Hydraulic Control Monitoring Program 2.75 $3,500 $3,500
1.2 Develop discharge and TDS mass balance and estimate residual discharge/TDS terms (2004 through present) 5.5 $7,420 $7,420
1.3Review mass balance tables and develop preliminary conclusions of the cause(s) of TDS exceedance; prepare Excel workbook for the Task Force
6.5 $9,160 $9,160
1.4 Prepare PowerPoint Presentation and meet with Task Force to present and discuss preliminary conclusions 3.25 $4,330 $68 $53 $121 $4,451
1.5 Revise discharge and TDS mass balance estimates based on Task Force comments; finalize conclusions 1.5 $2,110 $2,110
$7,780 $0 $7,780 2.1 Prepare draft letter report 4.25 $5,830 $5,830
2.2 Finalize letter report based on Task Force comments 1.5 $1,950 $1,950
Project Totals 25 $34,300 $53 $121 $34,421
Task 2 - Prepare Technical Memorandum (Optional)
Sub-Task Task
Task Project
Task 1 - Identify Cause(s) of TDS Exceedances
Repro-duction
Total ODCs
Person Days
CostSub-Task Task
Total Labor
Travel
Table 1Work Breakdown Structure and Fee Estimate
Investigate and Characterize the Cause(s) of Recent Exceedances of the TDS Objective for Reach 3 of the Santa Ana River
Description
Labor Other Direct ChargesTotal Program Costs
Total Dissolved Solids (TDS) for Santa Ana River Below Prado Dam
*Note: USGS data from August 30th appears to be an outlier. There is less than a 1-in-10,000 probability that the value reported for Aug. 30
th came from the same data distribution as the other 13 data points. And, in a
cumulative distribution function of all 14 data points, including August 30th
, the value of 527 mg/L is below the 0.5th percentile (less than one-half of 1%). Therefore, the USGS data for August 30th was excluded from all calculations.
Data Source 2013 Date Range* n Mean
OCWD Only Aug. 5th thru Sept. 10th 5 713 mg/L
OCWD + USGS Aug. 5th thru Sept. 10th 10 695 mg/L
OCWD + USGS Aug. 5th thru Sept. 26th 13 692 mg/L
OCWD + USGS August Only 7 707 mg/L
OCWD Only August Only 4 726 mg/L
Row # Station ID Source Result Units Sample Date
1 11074000 USGS 712 mg/L 8/5/2013
2 8105 OCWD 716 mg/L 8/6/2013
3 8105 OCWD 770 mg/L 8/13/2013
4 11074000 USGS 699 mg/L 8/14/2013
5 11066460 USGS 638 mg/L 8/16/2013
6 8105 OCWD 718 mg/L 8/20/2013
7 8105 OCWD 698 mg/L 8/27/2013
8 11066460 USGS 527 mg/L 8/30/2013
9 11074000 USGS 691 mg/L 9/4/2013
10 8105 OCWD 662 mg/L 9/10/2013
11 11066460 USGS 644 mg/L 9/10/2013
12 11074000 USGS 711 mg/L 9/13/2013
13 11066460 USGS 620 mg/L 9/26/2013
14 11074000 USGS 716 mg/L 9/26/2013
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