m (→Box 57) |
m (→Box 62) |
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Line 770: | Line 770: | ||
*Shallow groundwater or shallow bedrock is present within 3 feet of the bottom of the BMP and the BMP cannot be relocated or raised in elevation to achieve a 3 foot or greater separation from bedrock or groundwater. | *Shallow groundwater or shallow bedrock is present within 3 feet of the bottom of the BMP and the BMP cannot be relocated or raised in elevation to achieve a 3 foot or greater separation from bedrock or groundwater. | ||
[https://stormwater.pca.state.mn.us/index.php?title=MIDS_design_sequence_flow_chart#Box_31 Yes] | [https://stormwater.pca.state.mn.us/index.php?title=MIDS_design_sequence_flow_chart#Box_31 Yes] | ||
− | *Contaminated soil, contaminated groundwater, or hotspot runoff is present on the site and cannot be isolated or mitigated | + | *Contaminated soil, contaminated groundwater, or hotspot runoff is present on the site and cannot be isolated or mitigated |
− | [ | + | [https://stormwater.pca.state.mn.us/index.php?title=MIDS_design_sequence_flow_chart#Box_35 Yes] |
− | *Soils on the site have an infiltration rate of less than 0.2 inches per hour, the BMP cannot be relocated to | + | *Soils on the site have an infiltration rate of less than 0.2 inches per hour, the BMP cannot be relocated to areas with a higher infiltration rate, and the BMP cannot be sized to drain within 48 hours (24 hours in locations that are tributary to trout streams) |
− | [ | + | [https://stormwater.pca.state.mn.us/index.php?title=MIDS_design_sequence_flow_chart#Box_41 Yes] |
− | *Soils on the site have an infiltration rate greater than 8 inches per hour, the BMP cannot be relocated to an area with an infiltration rate lower than 8 inches per hour, | + | *Soils on the site have an infiltration rate greater than 8 inches per hour, the BMP cannot be relocated to an area with an infiltration rate lower than 8 inches per hour, or the subgrade cannot be modified to slow the infiltration rate to less than 8 inches per hour |
− | [ | + | [https://stormwater.pca.state.mn.us/index.php?title=MIDS_design_sequence_flow_chart#Box_45 Yes] |
*Soils on the site have an infiltration rate of less than 0.2 inches per hour, the BMP cannot be relocated to areas with an infiltration rate greater than 0.2 inches per hour, the BMP cannot be sized to drain within 48 hours (24 hours in locations that are tributary to trout streams), and Flexible Treatment Option 1 is feasible. | *Soils on the site have an infiltration rate of less than 0.2 inches per hour, the BMP cannot be relocated to areas with an infiltration rate greater than 0.2 inches per hour, the BMP cannot be sized to drain within 48 hours (24 hours in locations that are tributary to trout streams), and Flexible Treatment Option 1 is feasible. | ||
[https://stormwater.pca.state.mn.us/index.php?title=MIDS_design_sequence_flow_chart#Box_60 Yes] | [https://stormwater.pca.state.mn.us/index.php?title=MIDS_design_sequence_flow_chart#Box_60 Yes] |
Did you gather the site information necessary to proceed through the flow chart?
Prior to using the flow chart, gather the following preliminary information.
Does project create one acre or more of new and/or fully reconstructed impervious surfaces?
PREVIOUS QUESTION and ANSWER: The previous question defined the performance goals.
MIDS PERFORMANCE GOAL DOES NOT APPLY
The project creates less than 1 acre of impervious surface.
Is the project linear?
PREVIOUS QUESTION and ANSWER: Does project create one acre or more of new and/or fully reconstructed impervious surfaces? Answer - Yes
Are there constraints due to lack of available ROW, off site drainage and/or rate control requirements?
Is Flexible Treatment Option (FTO) 2 feasible?
PREVIOUS QUESTION and ANSWER: Are there restraints due to lack of available right-of-way, off-site drainage, and/or rate control requirements? Answer: Yes
Select Flexible treatment Option 2. You have completed the flow chart.
Applicant attempts to comply with the following conditions:
PREVIOUS STEP: It was determined that the site is linear, there are constraints due to lack of right-of-way or off/site drainage and/or rate control requirements, and a reasonable effort to acquire all of the right-of-way cannot be made.
Off-site mitigation (including banking or cash or treatment on another project, as determined by the local authority) equivalent to the volume reduction performance goal can be used in areas selected in the following order of preference:
PREVIOUS QUESTION: It was determined that Flexible Treatment Option 2 is not feasible.
Are there zoning and land use requirements that make the Performance Goal not feasible?
PREVIOUS QUESTION and ANSWER:
or
Is BMP relocation feasible
PREVIOUS QUESTION and ANSWER: Are there zoning and land use requirements that make the Performance Goal not feasible? Answer: Yes
Is Flexible Treatment Option (FTO) 1 feasible?
PREVIOUS QUESTION and ANSWER: Is BMP relocation feasible - Answer: No
Applicant attempts to comply with the following conditions:
Is Flexible Treatment Option (FTO) 2 feasible?
==PREVIOUS QUESTION and ANSWER: Is Flexible Treatment Option (FTO) 1 feasible? - Answer: No
Applicant attempts to comply with the following conditions:
Is the site located in a DWSMA (Drinking Water Supply Management Area), wellhead protection area, or within 200 feet of a drinking water well?
PREVIOUS QUESTION and ANSWER:
or
A drinking water supply management area (DWSMA) is the Minnesota Department of Health (MDH) approved surface and subsurface area surrounding a public water supply well that completely contains the scientifically calculated wellhead protection area and is managed by the entity identified in a wellhead protection plan. The boundaries of the drinking water supply management area are delineated by identifiable physical features, landmarks or political and administrative boundaries.
Can a Local Government Unit (LGU) provide a higher level of engineering review to ensure a functioning system that prevents adverse impacts to groundwater?
PREVIOUS QUESTION and ANSWER: Is the site located in a DWSMA, Wellhead Protection Area, or within 200 feet of a drinking water well? - Answer: Yes
Are there existing or proposed structures or infrastructure (e.g. rate control BMPs, utilities, buildings, roadway, easements) that make the Performance Goal not feasible?
PREVIOUS QUESTION and ANSWER:
or
Is BMP relocation feasible?
PREVIOUS QUESTION and ANSWER: - Are there existing or proposed structures or infrastructure (e.g. rate control BMPs, utilities, buildings, roadway, easements) that make the Performance Goal not feasible? - Answer: Yes
Is Flexible Treatment option (FTO) 1 feasible?
PREVIOUS QUESTION and ANSWER: Is BMP relocation feasible? - Answer: No
Is Flexible Treatment Option (FTO) 2 feasible?
PREVIOUS QUESTION and ANSWER: Is Flexible Treatment Option (FTO) 1 feasible? - Answer: No
Applicant attempts to comply with the following conditions:
Is karst present on the site?
If you are unsure, we recommend you review the guidance for karst in this manual. To retain your place in this flowchart, either open the karst guidance page in a new tab (right click on the link and select Open Link in New Tab), use the back arrow after visiting the karst guidance page, or use the Breadcrumbs at the top of the page.
PREVIOUS QUESTION and ANSWER:
or
Can a local unit of government (LGU) provide a higher level of engineering review to ensure a functioning system that prevents adverse impacts to groundwater?
PREVIOUS QUESTION and ANSWER: Is karst present on the site? - Answer: Yes
Is BMP relocation onsite to a location without karst feasible?
PREVIOUS QUESTION and ANSWER: Can a local unit of government (LGU) provide a higher level of engineering review to ensure a functioning system that prevents adverse impacts to groundwater? - Answer: No
Is Flexible Treatment Option (FTO) 2 feasible?
PREVIOUS QUESTION and ANSWER: Is BMP relocation onsite to a location without karst feasible? - Answer: No
Select Flexible treatment Option 2
Applicant attempts to comply with the following conditions:
You have completed the flow chart
Is shallow groundwater or shallow bedrock present on site?
If you are unsure, we recommend you review the guidance for shallow groundwater in this manual. To retain your place in this flowchart, either open the shallow groundwater guidance page in a new tab (right click on the link and select Open Link in New Tab), use the back arrow after visiting the shallow groundwater guidance page, or use the Breadcrumbs at the top of the page.
PREVIOUS QUESTION and ANSWER:
or
or
Conduct a detailed site investigation of shallow groundwater or shallow bedrock
PREVIOUS QUESTION and ANSWER: Is shallow groundwater or shallow bedrock present on site? - Answer: Yes
Is there more than 3 feet of soil depth from bottom of BMP to bedrock or groundwater (more than 10 feet is preferred)?
PREVIOUS STEP: You were asked to conduct a detailed site investigation of shallow groundwater or shallow bedrock
Is BMP relocation onsite to avoid shallow groundwater or shallow bedrock feasible?
PREVIOUS QUESTION and ANSWER: Is there more than 3 feet of soil depth from the bottom on the BMP to bedrock and groundwater (more than 10 feet is preferred)? - Answer: No
Can the BMP be raised?
PREVIOUS QUESTION and ANSWER: Is BMP relocation onsite to avoid shallow groundwater and shallow bedrock feasible? - Answer: No
Select Flexible treatment Option 2
Applicant attempts to comply with the following conditions:
PREVIOUIS STEP: It was determined that shallow groundwater or shallow bedrock is present within 3 feet of the bottom of the BMP and the BMP cannot be relocated or raised in elevation to achieve a 3 foot or greater separation from bedrock or groundwater.
You have completed the flow chart
Raise BMP enough to ensure 3 feet (preferably 10 feet) of soil between bottom of BMP and top of bedrock and groundwater
PREVIOUS QUESTION and ANSWER Can the BMP be raised? Answer - Yes
Is there presence of contaminated soils and/or contaminated groundwater, or hotspot runoff?
PREVIOUS QUESTION and ANSWER:
or
or
or
Can hotspot or contamination be isolated or remediated to mitigate risk of increased contamination?
PREVIOUS QUESTION and ANSWER: Is there presence of contaminated soils and/or contaminated groundwater, or hotspot runoff? - Answer: Yes
Select Flexible treatment Option 2
Applicant attempts to comply with the following conditions:
PREVIOUS STEP: It was determined that contaminated soil, contaminated groundwater, or hotspot runoff is present on the site and cannot be isolated or mitigated.
You have completed the flow chart
Are there very low infiltrating soils (less than 0.2 inches per hour) on site?
PREVIOUS QUESTION and ANSWER:
or
Is BMP relocation onsite to a higher-infiltrating location feasible?
PREVIOUS QUESTION and ANSWER: Are there very low infiltrating soils (less than 0.2 inches per hour) on site? - Answer: Yes
Can BMP be sized to drain dry within 48 hours (24 hours in locations that are tributary to trout streams)?
PREVIOUS QUESTION and ANSWER: Is BMP relocation onsite to a higher-infiltrating location feasible? - Answer: No
Provide soil boring or infiltration test results documenting low-infiltration soils.
PREVIOUS QUESTION and ANSWER: Can BMP be sized to drain within 48 hours (24 hours in locations that are tributary to trout streams)? Answer: No
Is Flexible Treatment Alternative No 1 feasible, allowing BMP to drain in 48 hours?
PREVIOUS STEP: You were asked to provide soil boring or infiltration test results documenting low-infiltration soils.
Select Flexible treatment Option 2
Applicant attempts to comply with the following conditions:
PREVIOUS STEP: It was determined that soils on the site have an infiltration rate of less than 0.2 inches per hour, the BMP cannot be relocated to areas with a higher infiltration rate, and the BMP cannot be sized to drain within 48 hours (24 hours in locations that are tributary to trout streams)
You have completed the flow chart
Are there very high infiltrating soils (more than 8 inches per hour) on site?
PREVIOUS QUESTION and ANSWER:
or
or
Is BMP relocation onsite to a lower-infiltrating location feasible?
PREVIOUS QUESTION and ANSWER: Are there very high infiltrating soils (more than 8 inches per hour) on site? - Answer: Yes
Can subgrade be modified to slow the rate of infiltration to less than 8 inches per hour?
PREVIOUS QUESTION and ANSWER: Is BMP relocation onsite to a lower-infiltrating location feasible? - Answer: No
Select Flexible treatment Option 2
Applicant attempts to comply with the following conditions:
PREVIOUS QUESTION and ANSWER
You have completed the flow chart
Are there adverse surface water hydrologic impacts from infiltration practices (e.g. impacting perched wetland)?
PREVIOUS QUESTION and ANSWER: Are there very high infiltrating soils (greater than 8 inches per hour) present on site)? - Answer: No or
or
Can the BMP be relocated to avoid adverse hydrologic impacts?
PREVIOUS QUESTION and ANSWER: Are there adverse surface water hydrologic impacts from infiltration practices (e.g. impacting perched wetland)? - Answer: Yes
Would BMPs accomodating Flexible treatment option 1 avoid adverse hydrologic impacts?
PREVIOUS QUESTION and ANSWER: Can the BMP be relocated to avoid adverse hydrologic impacts? - Answer: No
Select FTO Alternative No. 2
Applicant attempts to comply with the following conditions:
You have completed the flow chart
Select FTO Alternative No. 1
Applicant attempts to comply with the following conditions:
You have completed the flow chart
Complete design using the following performance goals
You have completed the flow chart
Do the following conditions apply?
and
Do the following conditions apply?
and
PREVIOUS QUESTION and ANSWER: You determined that Flexible Treatment Option 2 is feasible and there are no limitations resulting from zoning and land use requirements.
Do any of the following conditions apply? (NOTE: If any condition applies, you do not need to answer the remaining questions.)
Do the following conditions apply?
and
PREVIOUS QUESTION and ANSWER You determined that Flexible Treatment Option 2 is feasible and there are no limitations resulting from zoning and land use requirements.
Select Flexible Treatment Option (FTO) 2
Applicant attempts to comply with the following conditions:
PREVIOUS STEP: It was determined that the site is located within a DWSMA, wellhead protection area or within 200 feet of a drinking water well and infiltration is not allowed by the LGU.
You have completed the flow chart
Do any of the following conditions apply? (NOTE: If any condition applies, you do not need to answer the remaining questions.)
[Box 52 No]
PREVIOUS STEP: You determined that flexible Treatment option 1 is feasible.
Is Flexible Treatment Option 2 feasible?
Applicant attempts to comply with the following conditions:
Do the following conditions apply?
[ Box 45 Yes]
PREVIOUS QUESTION and ANSWER: Is Flexible Treatment Alternative No 1 feasible, allowing BMP to drain in 48 hours? - Answer: Yes
Do the following conditions apply?
Are there existing or proposed structures or infrastructure that make Flexible Treatment Option 1 not feasible?
[ Box 20 Yes]
PREVIOUS STEP: You determined that flexible Treatment option 1 is feasible.
Do any of the following conditions apply? (NOTE: If any condition applies, you do not need to answer the remaining questions.)
PREVIOUS STEP: You determined that Flexible Treatment Option 1 is feasible.
Do the following conditions apply?
Select Flexible Treatment Option (FTO) 2
Applicant attempts to comply with the following conditions:
PREVIOUS STEP: It was determined that
You have completed the flow chart
Select Flexible Treatment Option (FTO) 2
Applicant attempts to comply with the following conditions:
PREVIOUS STEP: It was determined that
You have completed the flow chart
Is Flexible Treatment Option (FTO) 2 feasible?
PREVIOUS QUESTION and ANSWER: Can the BMP be raised? - Answer: No