Public Information Meeting May 6, 2020 Lake Pepin Watershed TMDL Instructions for WebEx meeting participants: 1. Keep your voice (computer or phone) muted to avoid background noise • Use the microphone icon on your screen to mute (red when muted) 2. Preserve bandwidth by not using video 3. Questions will be taken via the chat box at first (by voice if time) • Chat box is accessed through the speech bubble icon on your screen Presentations will start at 10:05 am Chat Mute (Red when muted)
88
Embed
Lake Pepin Watershed TMDL...Agenda for today’s meeting Implementing the Lake Pepin Watershed study Dave Wall Research scientist for Nutrient Reduction Strategy Agenda for today’s
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Public Information Meeting
May 6, 2020
Lake Pepin Watershed TMDL
Instructions for WebEx meeting participants: 1. Keep your voice (computer or phone) muted to avoid background noise
• Use the microphone icon on your screen to mute (red when muted)2. Preserve bandwidth by not using video 3. Questions will be taken via the chat box at first (by voice if time)
• Chat box is accessed through the speech bubble icon on your screen
Presentations will start at 10:05 amChatMute
(Red when muted)
Welcome
Wayne CordsRegional and watershed manager
Lake Pepin Watershed TMDL open for public comment through June 19
Comments important
Agenda for today’s meeting
Overview of Lake Pepin Watershed studyJustin WatkinsWatershed supervisor and TMDL
project manager
Agenda for today’s meeting
Is water quality improving in watershed?Lee GanskeSupervisor of Watershed Pollutant
Loading Network
Agenda for today’s meeting
Implementing the Lake Pepin Watershed studyDave WallResearch scientist for Nutrient
Reduction Strategy
Agenda for today’s meeting
5-minute breakDetails on wastewater and stormwater permitsQuestionsUse your chat featureWayne will read questions out loud and direct them for
responses
Agenda for today’s meeting
Questions for MPCA team, including:Marco Graziani, TMDL and
wastewater coordinatorDuane Duncanson, municipal
stormwater supervisorHans Holmberg, LimnoTech
project consultant
More information
Justin Watkins [email protected] Wood Lake Drive SE, Rochester, MN 55904
Lake Pepin and Mississippi Riverwater quality studies
Project overview Watershed pollutant load monitoring update MN Nutrient Reduction Strategy Detail modules for wastewater and MS4s
Justin Watkins
Lee Ganske
Dave Wall
Justin Watkins
Wasteload allocations
TMDL component
Describes allowable load for point source
Used in setting wastewater effluent limits
Wasteload allocation approach for wastewater
Categorical: wasteload allocations based on facility type and size
Described in detail in TMDL document Section 5.2.1
Wasteload allocation approach for wastewater
Assigns wasteload allocation phosphorus mass to each facility
Appendix B includes each wasteload allocation
To be used in permitting
Lake Pepin TMDL wasteload allocation approachFacility Type and Flow (AWWDF or MDF*) Annual WLA to meet Lake Pepin TMDL
Continuous > 20.0 mgd AWWDF x 0.3 mg/L
Continuous 1.0 – 20.0 mgd AWWDF x 0.8 mg/L
Continuous 0.2 – 1.0 mgd AWWDF x 1.0 mg/L
Continuous <0.2 mgd AWWDF x 3.50 mg/L or maintain current load
Stabilization ponds AWWDF x 1.0 or 2.0 mg/L or maintain current load
WWTPs at conc. below River Eutrophication Standard Maintain current discharge**
Industrial Discharge with concentration > 1.0 mg/L and MDF > 1.0 mgd MDF x 1.0 mg/L
Industrial Discharge with concentration > 1.0 mg/L and MDF < 1.0 mgd MDF x 1.0 mg/L
Industrial Discharge with concentration < 1.0 mg/L Current load x 1.15
Other Industrial Limits specified on a site specific basis
WLAs will be implemented as 12 month moving total or calendar year total mass limit**Expansion of these WWTPs may be permitted assuming effluent concentration remains below River Eutrophication Standard
WWTPs collectively are already meeting the draft wasteload allocation of 600 metric tons year for Lake Pepin
WWTPs have been issued Lake Pepin limits when their permits expired since 2010
Many facilities are currently complying with proposed WLAs
Many WWTF WLAs already implemented
Phosphorus from wastewater dramatically reduced
Approx 238 permits with annual mass limits that are consistent with Pepin requirements
Summary
Many municipal and industrial wastewater permits already contain effluent limits that are consistent with TMDL wasteload allocations
How does a permittee find out if they need to make changes? Reach out to MPCA and we will
connect
Lake Pepin TMDLMunicipal Industrial Total
Facilities with WLAs 260 137 397Permit limits Consistent with TMDL WLA 195 31 226Permit limits need adjustment 20 6 26No existing permit limit 45 100 145
Mississippi River RES TMDLsMunicipal Industrial Total
Facilities with WLAs 33 37 70Permit limits Consistent with TMDL WLA 15 9 24Permit limits need adjustment 14 2 16No existing permit limit 4 28 32
Note: Many industrial discharges do not contain elevated phosphorus concentrations and will not need effluent limits or, if they do, they are likely to be able to meet those limits already. Individual permit by permit analysis will be needed to determine this. Examples of such discharges include noncontact cooling water and sand & gravel pit dewatering.
Wasteload allocations
TMDL Component Describes allowable load for
point source Used in MS4 permitting MS4: Municipal Separate
Stormsewer System
Wasteload allocation approach for MS4s
Based on phosphorus export goal 0.35 lb/acre/year total phosphorus Not a “flat reduction percentage” Per previous MS4 stakeholder input
See TMDLs document Section 5.2.2
Based on literature & data
Consistent with other phosphorus TMDLs
Wasteload allocation approach for MS4s
Real data indicate this export rate is reasonably achievable
WLA masses are 0.35 lb/acre multiplied by MS4 regulated areasIncluded in Appendix C
Literature review to determine export number
Detailed Assessment of Phosphorus Sources to Minnesota Watersheds (Barr Engineering 2004)
Lake St. Croix Nutrient TMDL (MPCA 2012b) (0.337 lb/acre/year) Lake Byllesby TMDL (MPCA 2013b) (0.242 lb/acre/year) Medicine Lake TMDL (MPCA 2010) (0.279 lb/acre/year) Coon Creek TMDL (MPCA 2016b) (0.392 lb acre/year) Minnesota River DO TMDL (MPCA 2004) Upper Mississippi River – Lake Pepin Water Quality Model (LimnoTech
2009a) Cannon River HSPF Model (LimnoTech 2015).
Non-degradation estimates
Loading estimates for 30 non-degradation cities in MN
Estimated loads for “No BMPs” and “With BMPs” scenarios
If a “typical” no BMPs export is approximately 0.5 lb/acre/yr, a 30% reduction would get to the export goal Consistent with MN River DO TMDL
Metropolitan Council phosphorus export data
WLA application in MS4 permits
Need to show progress toward numeric goals For MS4s that have more restrictive local WLAs, those WLAs represent
the working goals Phosphorus BMPs can be credited to multiple WLAs Note that the new MS4 permit requires permittees to address WLAs
that are finalized at the time of MS4 permit completion It is likely that the Lake Pepin and Mississippi River TMDLs will be finalized
after the MS4 permit and as such, these WLAs will be addressed in next permit cycle; so there is reasonable amount of time to integrate these numbers in plans and permits
Questions?Comments due 4:30 p.m. June 19:in Watkins