Replies

1. GBA Editor
   Martin Holladay | Oct 29, 2018 05:36am | #1

   Mateo,
   It would take a site visit to evaluate all of the possibilities. But if the situation is as you describe it -- your house is in a bowl -- you're not in a good situation.

   In some communities, it is legal to connect a sump pump to the municipal drain system (either the sewer lines or a separate storm drainage system, if your town has such a system). You may need to install a sump pump in your crawlspace, and try to obtain permission from your local authorities to connect the sump pump drain to municipal drain pipes.

1. 
   mateohao | Oct 29, 2018 09:51pm | #4

   Thanks for the tip, Martin.

   The rules where I live changed and any sewer lateral work must disconnect any storm water plumbing to avoid overloading the sewer system.

   I will see if my municipality is able to give exceptions.

2. Expert Member
   Peter Engle | Oct 29, 2018 08:20am | #2

   Mateo,

   I'm not sure I understand about the back yard. Do you mean that your property slopes from front to back? if so, that creates some possibility of catching the surface water using some combination of pavements, swales and/or drains, and then disposing of the water in the back.

   We don't know your location (zipcode please?). As Martin said, a well-designed solution would require a site visit. Depending on rainfall amounts and the surface areas draining toward you, a rain garden in the back yard may be a good solution. If you are really sitting in a clay bowl, some sort of sump pump to either the street or to storm/combined sewer system might be your only solution.

   You may be able to have a conversation with the owner of the zero lot line property. Most towns have ordinances about disposing of stormwater on someone else's property, and if their water is damaging your house you might have some recourse.

1. 
   mateohao | Oct 29, 2018 10:55pm | #5

   Hi Peter,

   I am in Oakland, CA. The first 10 feet behind my house is relatively flat. The remaining 40 feet rises 13 feet toward the back property line. There are two more blocks of houses uphill behind me. The idea I was describing was something like a ditch behind my house to allow water to go away from my house and intercept runoff from the hill behind me.

   Geography-wise, I am at the base of a terrace made from alluvial materials. The street in front of me used to be a creek that ran into the bay. Summers are mild and it rains near the end of winter, with an average of 24 inches of rainfall. This April an inch of rain over one night deposited over a foot of water in my crawlspace and it took about 24 hours for it to seep away.

   I most definitely experience runoff from other people's property. I will see if the city can help me with that.

   I'm looking at soil engineers now.

   Thanks!

3. 
   jaccen | Oct 29, 2018 12:08pm | #3

   What's your location? If you're in an urban area, there should be a stormwater management area plan for your location. You can request the as-builts from your local municipality. This will let you know the planned storm outlet location and what the plan for the flows across your property is.

   If you can't convey flows, you can attempt to infiltrate them depending on the amounts. Please note that, depending on your soil type, infiltrating water may have adverse effects on a basement. Is your crawlspace above the water table? What is the permeability of your clay soil type? If research and calculations are not your forté, it may be worth involving an engineer depending on your end goals and your budget. Your municipality may also have bylaws dictating what can and can't be done so it's best to check with them.

   If you're in Ontario, these may be of help:

   4.1.1 Lot level and conveyance controls
   https://www.ontario.ca/document/stormwater-management-planning-and-design-manual/stormwater-management-plan-and-swmp-design

   Infiltration-based controls include:
   -reduced grading to allow greater ponding of stormwater and natural infiltration;
   -directing roof leaders to rear yard ponding areas, soakaway pits, or to cisterns or rain barrels;
   -sump pumping foundation drains to rear yard ponding areas;
   -infiltration trenches;
   -grassed swales;
   -pervious pipe systems;
   -vegetated filter strips; and
   -stream and valley corridor buffer strips.

   Stormwater Management Planning and Design Manual
   http://www.ontla.on.ca/library/repository/mon/5000/10302166.pdf

   Figure 4.1 and onward are illustrations of the above lot grading and infiltration methods.

   Some GBA articles of interest:

   Stormwater Management
   https://www.greenbuildingadvisor.com/green-basics/stormwater-management

   Stormwater: Rain Gardens and Drywells
   https://www.greenbuildingadvisor.com/green-basics/stormwater-rain-gardens-and-drywells

   Zen and the Art of Grading
   https://www.greenbuildingadvisor.com/article/zen-and-the-art-of-grading

   All About Dry Wells
   https://www.greenbuildingadvisor.com/article/all-about-dry-wells

   A good overview of ..... everything (a bit over the top, but good reading for the "whole" picture)
   http://www.civil.ryerson.ca/stormwater/menu_1/index.htm

1. 
   mateohao | Oct 29, 2018 11:00pm | #6

   Hello Jaccen,

   I live in Oakland, California. The neighborhood around me is all hills and ancient creeks and a big lake draining into the Bay. There most definitely is a storm water management plan. I will check with the city.

   The references you provided are great!

   I think I will be calling a soil engineer now.

   Thank you.
   -M

4. 
   jaccen | Nov 02, 2018 09:10am | #7

   I'm not familiar with Engineering Design standards in Oakland, but this would be a good starting point for background information:
   http://www2.oaklandnet.com/government/o/PWA/o/EC/s/DGP/SDDS/index.htm

   It has some good, high-level info.

   This link also yielded some decent links and contacts:
   www2.oaklandnet.com/w/DOWD009623

   Local Information and Resources
   American Rainwater Catchment Systems Association (ARCSA):
   http://www.arcsa.org
   The Alameda County Mosquito Abatement District: Mosquito breeding prevention tips http://www.mosquitoes.org
   Low Impact Development Center, Inc.:
   http://www.lowimpactdevelopment.org
   Watershed and Stormwater management Program:
   [email protected]
   Urban Farmer:
   wwww.urbanfarmerstore.com
   (510) 524-1604

   For reference, a T-time/perc test here in Ontario costs about $200 to $300 (CDN dollars.......so about $5 Monopoly money for our friends to the south ;) ). It would tell you how quickly water moves through your dirt. If you know you have clay, you may not need it and can just use a worst-case scenario to save you some money.
   https://en.wikipedia.org/wiki/Percolation_test

   I would talk with the municipality about what is acceptable and what's already planned for your area before going too far along implementing a plan. Asking questions and doing your own planning is free. Designing a Low Impact Development (LID) control if it's not allowed would only waste your time and money.

   That being said, the CVCA has a pretty good manual available:
   https://cvc.ca/low-impact-development/low-impact-development-stormwater-management-planning-design-guide/

   Showing my Ontario bias again, they're the agency pushing hard for LID controls to better control stormwater on-site before it gets to the roadways/waterways.

5. 
   Poliana | Nov 17, 2018 09:49pm | #8

   I think I have the same situation like you. I live in NY