Form 1 Q4 & Q5

I put 2 questions in one here, maybe makes it easier.

This question was about a site in a forested area, and how to make a defensible space from fire.
Which of the following actions complies with best practices for maintaining defensible space? Check the four that apply.
I got half of it right the part I didn’t get is it says store firewood uphill from the building, and reduce forest density within 100ft of the building mentioning zones 1 and 2.

How does storing firewood uphill protect a building from fire?
What zones are these referring to, and how do you go about these types of questions?

I get that vegetation should be avoided around a building because it could get on fire, but shrubs should be spaced about 20ft not 100ft, I guess it’s kind of obvious 100ft is too big, are there charts or diagrams I can get this content or is this more like analyze and make reason with it kind of question?

The other question below, I got half wrong as well, I get that following local hazard regulations and grading ordinances are ideal. The question below mentions,
An architect has been hired to design a private residence in an area that is moderately susceptible to landslides.
Which steps should be taken to minimize slope destabilization? Check the four that apply.

The part I got wrong was alternatives to septic systems, I guess how does a septic system increase the potential for slope destabilization and landslides?
Also how does utilizing up-slope fill to create the building pad create unstable soil conditions?

@coachchrishopstock can you please take a look into these questions?


Hi @sergioclaure93 and thanks for the questions!
For the one about defensible spaces relative to wildfires, see Planning and Urban Design Standards, Page 219. One of the reasons not to store firewood downhill from a structure is that if that firewood ignites and it’s downhill, the flames will rise and with wind, could come in contact with the home. If the firewood is uphill, theoretically the flames from an ignited pile of wood would be higher than the downhill structure, reducing the likelihood of it catching fire as well.
Regarding the spacing of shrubs and trees noted in this question - that information comes directly from page 219 of Planning and Urban Design Standards - I’m not aware of a diagram that shows this information.
The best advice I can give on a question like this, particularly a ‘check 4’ question, is to find the incorrect answers if you’re unsure. For this one, one incorrect answer is about non-native plant species, which doesn’t relate to the idea of protecting vs. wildfires (native and non-native species would both be susceptible to fire). The second incorrect answer is about planting shrubs 100’ apart - which is a much greater distance than is required to create defensible space. And think about how lonely those shrubs would be 100’ apart from each other!

For your second question - septic systems introduce liquid waste into the soil by means of the leaching field, which can have a slight destabilizing effect on the soil. The system should be designed so that it’s large enough that this effect is minimal, but it happens nonetheless. If you’ve ever noticed a mushier spot in a yard than the rest of the yard, it’s probably where the leaching field is! Typically local authorities have maximum allowable slopes that they allow a septic system to be placed on - in my area it’s 15% but it could be different elsewhere depending on the terrain and soil conditions.
Upslope fill is not a great option in an area susceptible to landslides because this type of fill creates an unnatural plateau on the land, adding weight to the already unstable soil conditions beneath.

Okay that makes sense I get the site scenario and concepts better, yeah I will review that book. Thanks!

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