Horizontal/Subsurface Infrastructure & Transportation

I have a facility owner that is interested to talk with other facility owners about their user experiences with parking lots designed to flood in intense storm events. Like most projects, they have quite a few compounding constraints and are looking at cost effective design alternatives to the fully contained UG detention system as currently designed. The CE of record has suggested a mix of the UG system and use of the parking area for 25 yr storms. I'm encouraged by the idea as I've seen projects throughout the western U.S. use this technique.

The owner will operate a religious facility and a day school and is curious if other owners with similar designs would do it again or if they are burdened by the occasional standing water in the parking areas. Are there any good resources or personal testimonies I can point them towards?

------------------------------
Jesse Kamm PhD, PMP, A.M.ASCE
Senior Vice President of Construction Management
------------------------------

Hello from California,

About 10 years ago I designed site improvements for a school on a  4 acre property with an existing church.  This is considered fairly large property-"near downtown"-- for an area with some of the highest land values in the US.  

Since construction, I've monitored performance on my own, and I have my own ideas of what I would do differently / better.  But we were not required to contain an event anywhere near a 25-year reoccurrence interval--I believe our requirement was say a 1-inch storm in 24 hours.

We currently have another site ---much smaller-which requires 5-year containment; this is an expensive undertaking--fortunately church members have deep pockets and determination to see their dream built.

And we just finished construction of a what I consider a sophisticated system for an industrial customer including underground storage tanks, pumps, controls and wiring like you'd see in a sewage treatment plant.

But it seems to me you folks face a very large challenge if you must absolutely contain a 25-year event, unless you a) are blessed with building on very permeable soil, b) have a huge site for retention basis, or c) have a huge budget.

Are you sure that containment of a "25-year storm" is the case?  Even a 10-year event totally contained will be a substantial undertaking.

------------------------------
Scott Onishuk M.ASCE
Santa Barbara CA
(805)563-0788
------------------------------

Thank you Scott,

The language the project civil engineer used has been the 25yr event thus far, but I'm not certain if he was speaking in descriptive terms or specific requirements. I will certainly clarify the specifics but in terms of the owner's interest, I suspect any rain event that causes cancellations could be concerning. You mentioned a 1-inch containment within a 24hr period on prior projects, to me that seems entirely feasible. From a user perspective, I might be a little annoyed that I have to walk through 1-inch of water to my car, but it wouldn't stop me from accessing my car and driving away. I'm currently awaiting the re-design of the mixed system and associated cost estimates. The initial design for the entirely contained underground system was about a quarter of the costs of the entire project!

------------------------------
Jesse Kamm PhD, PMP, A.M.ASCE
Senior Vice President of Construction Management
------------------------------

Original Message:
Sent: 02-28-2019 12:37
From: Scott Onishuk
Subject: Owner/user experiences with parking facilities designed for 25yr storm detention

Hello from California,

About 10 years ago I designed site improvements for a school on a  4 acre property with an existing church.  This is considered fairly large property-"near downtown"-- for an area with some of the highest land values in the US.

Since construction, I've monitored performance on my own, and I have my own ideas of what I would do differently / better.  But we were not required to contain an event anywhere near a 25-year reoccurrence interval--I believe our requirement was say a 1-inch storm in 24 hours.

We currently have another site ---much smaller-which requires 5-year containment; this is an expensive undertaking--fortunately church members have deep pockets and determination to see their dream built.

And we just finished construction of a what I consider a sophisticated system for an industrial customer including underground storage tanks, pumps, controls and wiring like you'd see in a sewage treatment plant.

But it seems to me you folks face a very large challenge if you must absolutely contain a 25-year event, unless you a) are blessed with building on very permeable soil, b) have a huge site for retention basis, or c) have a huge budget.

Are you sure that containment of a "25-year storm" is the case?  Even a 10-year event totally contained will be a substantial undertaking.

------------------------------
Scott Onishuk M.ASCE
Santa Barbara CA
(805)563-0788
------------------------------

I wanted to provide some conclusion by sharing the strategy we ultimately decided upon:
We took a four fold approach: (1) diverting some of the water from the new roof to an existing detention basin, (2) creating a new detention basin near an expanding roadway with deep encapsulating retaining walls and an architectural/hardscape element forward facing to the public, (3) converted the parking lot islands to "rain gardens" with an underground diversion system, and (4) permeable paving with parking lot detention in limited areas.

Using this combined strategy we were able to reduce the site budget by nearly 65%. Thanks again.

------------------------------
Jesse Kamm PhD, PMP, A.M.ASCE
Senior Vice President of Construction Management
------------------------------

Original Message:
Sent: 03-04-2019 09:19
From: Jesse Kamm
Subject: Owner/user experiences with parking facilities designed for 25yr storm detention

Thank you Scott,

The language the project civil engineer used has been the 25yr event thus far, but I'm not certain if he was speaking in descriptive terms or specific requirements. I will certainly clarify the specifics but in terms of the owner's interest, I suspect any rain event that causes cancellations could be concerning. You mentioned a 1-inch containment within a 24hr period on prior projects, to me that seems entirely feasible. From a user perspective, I might be a little annoyed that I have to walk through 1-inch of water to my car, but it wouldn't stop me from accessing my car and driving away. I'm currently awaiting the re-design of the mixed system and associated cost estimates. The initial design for the entirely contained underground system was about a quarter of the costs of the entire project!

------------------------------
Jesse Kamm PhD, PMP, A.M.ASCE
Senior Vice President of Construction Management
------------------------------


Original Message:
Sent: 02-28-2019 12:37
From: Scott Onishuk
Subject: Owner/user experiences with parking facilities designed for 25yr storm detention

Hello from California,

About 10 years ago I designed site improvements for a school on a  4 acre property with an existing church.  This is considered fairly large property-"near downtown"-- for an area with some of the highest land values in the US.

Since construction, I've monitored performance on my own, and I have my own ideas of what I would do differently / better.  But we were not required to contain an event anywhere near a 25-year reoccurrence interval--I believe our requirement was say a 1-inch storm in 24 hours.

We currently have another site ---much smaller-which requires 5-year containment; this is an expensive undertaking--fortunately church members have deep pockets and determination to see their dream built.

And we just finished construction of a what I consider a sophisticated system for an industrial customer including underground storage tanks, pumps, controls and wiring like you'd see in a sewage treatment plant.

But it seems to me you folks face a very large challenge if you must absolutely contain a 25-year event, unless you a) are blessed with building on very permeable soil, b) have a huge site for retention basis, or c) have a huge budget.

Are you sure that containment of a "25-year storm" is the case?  Even a 10-year event totally contained will be a substantial undertaking.

------------------------------
Scott Onishuk M.ASCE
Santa Barbara CA
(805)563-0788

Thank you for sharing your team's solution.  We use a lot of permeable pavers here in Southern California. One church--with many​ locations--uses them almost exclusively because they can be installed by the members.  I believe they've even bought their own equipment to handle all the material and take it from project-to-project.

Be aware of the drive path of your garbage truck and delivery docks, along with the location of the dumpsters/trash enclosures--so you have happy rolling.  Likely your team already thought of this; permeable pavers and dumpsters fight each other.


------------------------------
Scott Onishuk M.ASCE
Santa Barbara CA
(805)563-0788
------------------------------

Original Message:
Sent: 03-28-2019 09:45
From: Jesse Kamm
Subject: Owner/user experiences with parking facilities designed for 25yr storm detention

I wanted to provide some conclusion by sharing the strategy we ultimately decided upon:
We took a four fold approach: (1) diverting some of the water from the new roof to an existing detention basin, (2) creating a new detention basin near an expanding roadway with deep encapsulating retaining walls and an architectural/hardscape element forward facing to the public, (3) converted the parking lot islands to "rain gardens" with an underground diversion system, and (4) permeable paving with parking lot detention in limited areas.

Using this combined strategy we were able to reduce the site budget by nearly 65%. Thanks again.

------------------------------
Jesse Kamm PhD, PMP, A.M.ASCE
Senior Vice President of Construction Management
------------------------------


Original Message:
Sent: 03-04-2019 09:19
From: Jesse Kamm
Subject: Owner/user experiences with parking facilities designed for 25yr storm detention

Thank you Scott,

The language the project civil engineer used has been the 25yr event thus far, but I'm not certain if he was speaking in descriptive terms or specific requirements. I will certainly clarify the specifics but in terms of the owner's interest, I suspect any rain event that causes cancellations could be concerning. You mentioned a 1-inch containment within a 24hr period on prior projects, to me that seems entirely feasible. From a user perspective, I might be a little annoyed that I have to walk through 1-inch of water to my car, but it wouldn't stop me from accessing my car and driving away. I'm currently awaiting the re-design of the mixed system and associated cost estimates. The initial design for the entirely contained underground system was about a quarter of the costs of the entire project!

------------------------------
Jesse Kamm PhD, PMP, A.M.ASCE
Senior Vice President of Construction Management


Original Message:
Sent: 02-28-2019 12:37
From: Scott Onishuk
Subject: Owner/user experiences with parking facilities designed for 25yr storm detention

Hello from California,

About 10 years ago I designed site improvements for a school on a  4 acre property with an existing church.  This is considered fairly large property-"near downtown"-- for an area with some of the highest land values in the US.

Since construction, I've monitored performance on my own, and I have my own ideas of what I would do differently / better.  But we were not required to contain an event anywhere near a 25-year reoccurrence interval--I believe our requirement was say a 1-inch storm in 24 hours.

We currently have another site ---much smaller-which requires 5-year containment; this is an expensive undertaking--fortunately church members have deep pockets and determination to see their dream built.

And we just finished construction of a what I consider a sophisticated system for an industrial customer including underground storage tanks, pumps, controls and wiring like you'd see in a sewage treatment plant.

But it seems to me you folks face a very large challenge if you must absolutely contain a 25-year event, unless you a) are blessed with building on very permeable soil, b) have a huge site for retention basis, or c) have a huge budget.

Are you sure that containment of a "25-year storm" is the case?  Even a 10-year event totally contained will be a substantial undertaking.

------------------------------
Scott Onishuk M.ASCE
Santa Barbara CA
(805)563-0788

Mr. Onishuk,
It's interesting you mentioned the owner purchasing their own equipment to maintain and self-perform - particularly for multi-site churches. As I've progressed in my career, my relationships with clients have become very long term. That means we lament together some of the difficulties in maintaining and repairing their facilities. Nearly all my work is with non-profit organizations and this usually means a lot of good intentioned volunteers or pros offering pro bono services. When I was doing public projects I often had to provide maintenance tool kits as part of the project closeout but I've never seen that in private contracts.

------------------------------
Jesse Kamm PhD, PMP, A.M.ASCE
Senior Vice President of Construction Management
------------------------------

Original Message:
Sent: 03-28-2019 11:36
From: Scott Onishuk
Subject: Owner/user experiences with parking facilities designed for 25yr storm detention

Thank you for sharing your team's solution.  We use a lot of permeable pavers here in Southern California. One church--with many​ locations--uses them almost exclusively because they can be installed by the members.  I believe they've even bought their own equipment to handle all the material and take it from project-to-project.

Be aware of the drive path of your garbage truck and delivery docks, along with the location of the dumpsters/trash enclosures--so you have happy rolling.  Likely your team already thought of this; permeable pavers and dumpsters fight each other.


------------------------------
Scott Onishuk M.ASCE
Santa Barbara CA
(805)563-0788
------------------------------


Original Message:
Sent: 03-28-2019 09:45
From: Jesse Kamm
Subject: Owner/user experiences with parking facilities designed for 25yr storm detention

I wanted to provide some conclusion by sharing the strategy we ultimately decided upon:
We took a four fold approach: (1) diverting some of the water from the new roof to an existing detention basin, (2) creating a new detention basin near an expanding roadway with deep encapsulating retaining walls and an architectural/hardscape element forward facing to the public, (3) converted the parking lot islands to "rain gardens" with an underground diversion system, and (4) permeable paving with parking lot detention in limited areas.

Using this combined strategy we were able to reduce the site budget by nearly 65%. Thanks again.

------------------------------
Jesse Kamm PhD, PMP, A.M.ASCE
Senior Vice President of Construction Management


Original Message:
Sent: 03-04-2019 09:19
From: Jesse Kamm
Subject: Owner/user experiences with parking facilities designed for 25yr storm detention

Thank you Scott,

The language the project civil engineer used has been the 25yr event thus far, but I'm not certain if he was speaking in descriptive terms or specific requirements. I will certainly clarify the specifics but in terms of the owner's interest, I suspect any rain event that causes cancellations could be concerning. You mentioned a 1-inch containment within a 24hr period on prior projects, to me that seems entirely feasible. From a user perspective, I might be a little annoyed that I have to walk through 1-inch of water to my car, but it wouldn't stop me from accessing my car and driving away. I'm currently awaiting the re-design of the mixed system and associated cost estimates. The initial design for the entirely contained underground system was about a quarter of the costs of the entire project!

------------------------------
Jesse Kamm PhD, PMP, A.M.ASCE
Senior Vice President of Construction Management


Original Message:
Sent: 02-28-2019 12:37
From: Scott Onishuk
Subject: Owner/user experiences with parking facilities designed for 25yr storm detention

Hello from California,

About 10 years ago I designed site improvements for a school on a  4 acre property with an existing church.  This is considered fairly large property-"near downtown"-- for an area with some of the highest land values in the US.

Since construction, I've monitored performance on my own, and I have my own ideas of what I would do differently / better.  But we were not required to contain an event anywhere near a 25-year reoccurrence interval--I believe our requirement was say a 1-inch storm in 24 hours.

We currently have another site ---much smaller-which requires 5-year containment; this is an expensive undertaking--fortunately church members have deep pockets and determination to see their dream built.

And we just finished construction of a what I consider a sophisticated system for an industrial customer including underground storage tanks, pumps, controls and wiring like you'd see in a sewage treatment plant.

But it seems to me you folks face a very large challenge if you must absolutely contain a 25-year event, unless you a) are blessed with building on very permeable soil, b) have a huge site for retention basis, or c) have a huge budget.

Are you sure that containment of a "25-year storm" is the case?  Even a 10-year event totally contained will be a substantial undertaking.

------------------------------
Scott Onishuk M.ASCE
Santa Barbara CA
(805)563-0788