top of page

Assessing the Impact of a New Site for Vancouver's Daytox/Detox Centre

While bopping around in the twittersphere the other day, something I tend to do after my toddler is put to bed and a calm descends on our home, I came across a group concerned about the proposed site for the relocation of Vancouver's Daytox/Detox programme. My brain started mulling over the issues that they had raised and I couldn't shake the feeling that this required a closer look - which of course includes my good old friends: Spatial Analysis and Maps, which is why we are here. So here we go...



The current location is at 333 E 2nd Ave and is a Vancouver Coastal Health facility that offers outpatient withdrawal services for those aged 19 and older. Withdrawal programmes offered here last 6-weeks, are medically monitored and include a variety of resources such as counselling, acupuncture, and other services.


The proposed site at 1636 Clark Drive will provide a new, updated home for these services and will offer inpatient withdrawal support, which the current site does not, as well as housing through a mixed use development that is 5 stories high and provides 60-100 units for long term stays, and 20 short term beds for those who have completed the treatment. Additionally, BC Housing has proposed to offer social enterprise programmes, culturally appropriate services relevant to the neighbourhood, as well as be a teaching and knowledge sharing facility for staff and health providers. All in all, this proposal is an important improvement for those seeking support in their addiction and beyond.


That said, there are concerns from a residents' group have regarding the new location and the impact on the neighbourhood that are both legitimate and persuasive, and include:

  • Another BC Housing development less than 100m away from the proposed site and within 2 blocks there are almost 200 existing BC Housing units;

  • Safety for seniors, children and property due to the proximity of those being offered addiction related services; and

  • The building height shadow and potential to dwarf adjacent buildings.

In an effort to add clarity to what is sure to be an emotional issue, and to understand the potential effect of the site compared to the perceived impact, let's take a closer look at these concerns through an analytical lens mentioned in my opening paragraph...


According to listings on BC Housing's website, there are 374 buildings in the City of Vancouver that they oversee. These range in type of housing from low income family housing to seniors supportive housing, and everything in between (or at least pretty darned close). Buildings range in size from 3 units - a housing cooperative - to over 450 units - a subsidized housing option for seniors and those with disabilities. To satisfy my curiosity raised regarding the potential site, I needed to calculate the density of units and crime per hectare as can be seen in two maps below. To accomplish this I calculated the density of both BC Housing units for the below illustration and crime points as reported by the City of Vancouver (2017) further below.


Image 1: BC Housing Density of Units/ha - comparing current levels (brown) to proposed levels (blue).


Reviewing the maps above, as well as the data that is produced alongside these visualizations, it is notable that there are numerous pockets of BC Housing density (the map coloured yellow to brown) scattered throughout the City as well as in Grandview Woodlands somewhat proximal to the proposed site. That being said, it is hard to argue that this area represents the highest concentration of BC Housing units in the City! The densities of BC Housing units in the Downtown Core, Strathcona, and Downtown South and the West End are nearly double that of the light brown blob Southeast of 1st Ave. When we take a look at the effect of the new development (blue blobs), we can note that there is a small change in the overall density of BC Housing units in the area, but again not a tremendous effect when compared to the rest of the City.

Another way to look at this data is to take a look at the relationship between population density and density of BC Housing units. In an ideal world, each part of the City would have an equal proportion of BC Housing units to that of its total dwelling stock. However, we all know that is not the case. We ran some analysis on this which is presented in the scatter-plot chart below. The left axis is BC Housing dwelling density and the bottom axis is population density. Areas that are below the trendline (the dotted line that represents the relationship between Units and Population) are seeing less BC housing units than would be expected for their populations given the relationship depicted in the graph and areas above the line are showing more BC housing units than expected. In this instance we see that Grandview Woodlands is punching a bit above its weight in terms of BC Housing units versus population density, but it is in a similar league to Killarney in Southeast Vancouver, and is totally dwarfed by Downtown and Strathcona, which have the bulk of BC Housing units in the City

Figure 1: Graph showing the relationship between densities of BC Housing units and overall population density.


The next thing to look at was whether or not we could draw any causal links between the existing Daytox/Detox site and non-violent crime rates in the area. This was to address the statement that the new location of the site may lead to concerns with regards to the safety of children and seniors due to the proximity of addiction-related services. The two questions to answer are: Does the current facility generate a lot of crime and what is the current crime baseline at the location of the proposed site?

Image 2: Density of Reported Crimes/ha


In the above visualization, it is of note that there is no real crime "hot-spot" around the current site (red blobs indicate high crimes per hectare). While the density of crimes is generally higher in the area compared to Mount Pleasant as a whole, we could not draw any conclusions that they were being driven by the Detox/Daytox site. We should also note, that this a very high-level analysis, indeed a whole thesis can be written on the effects of addiction-related services and criminal activities (or any mislabeled "driver" and criminal activity for that matter). However, at this high-level it is inconclusive to suggest that there will be a reduction to personal safety were the site to be moved.


The following analysis is to explore the shade that the proposed building will cast on the neighbouring parcels and if and how much it would "dwarf" the neighbouring buildings. In the following images you will see our very rough 3d model of the proposed development, as well as a solar modeling based on angle of the sun and daylight hours and other objects that currently cast shade (namely trees and buildings) on surrounding properties.


Image 3: Before and after sketch of location and height of proposed building.


First Avenue between Clark and McLean is a very steep street. Based on the only high level sketch we could find of the site, it appears as if the structure will be approximately five stories at Clark and maintain a uniform roof line towards to McLean. In terms of massing, the site will be bigger, but the slope of the street and the presence of mature full foliage trees will do much to blunt this impact.

In terms of shading, the analysis is a bit more interesting. The two images below show a before and after sketch of what the total hours of sunshine will be at the location based on a solar model run for May 20th (a theoretical sunny day in spring/summer). Red colours indicate higher levels of sunshine per day and blue colours indicate fewer hours of sunshine per day. For example, with a quick glance it is easy pick out the shade cast by trees as dark blue and the red as open areas that get many more hours of sunlight.


Image 4: Before and after prediction of building shadow based on the height of the proposed building at 5 stories.


Based on the analysis, it was noted that there was increased shading mostly in the alleyway directly behind the proposed development and and to the west of the site on Clark Drive. There is not a lot of shading and infringement on neighboring properties due to two factors: first the site slopes off very steeply to the East, as shadows mainly fall in a Northeast to Southeast arc, and the shadows are basically eaten up by the hill. Second, the trees along 1st are very tall and have quite full foliage. These (if they are retained) already block out significant amounts of sunlight in this area.

To get a a more complete understanding of the impact, the next step is to compare the two cases directly by estimating the total loss of direct sunlight on May 20th (Image 5 below). In the image below, lighter colours indicate fewer hours of sunlight lost and bluer colours indicate greater amounts of sunlight lost. As has been mentioned, there will not be a tremendous amount of change on any neighbouring properties. Indeed, in terms of placing a big blocky building anywhere in Vancouver, this would have to be one of the best sites for reducing impacts to shading and sunlight.

Image 5: Estimation of total loss of direct sunlight hours.


From the above analyses the following outcomes were gathered:

  • Another BC Housing development is less than 100m away from the proposed site and within 2 blocks there are almost 200 existing BC Housing units: True but this is a drop in the bucket of BC Housing units in the City overall. Second, there are many other areas that have higher densities of BC Housing units.

  • Safety for seniors, children and property due to proximity to addiction related services: We did not note any large crime hot spots around the existing facility, therefore we cannot determine if there will be a negative impact to the safety of seniors, children and property due to the proximity of addiction related services.

  • The building height shadow and potential to dwarf adjacent buildings: Given the site conditions, the building will certainly mass larger than adjacent buildings but will have a lowered impact with regards to shading

In summary, what was attempted here is to include some data and analysis to answer potential community concerns. Many of these will be addressed in the coming days and months by project stakeholders as the project moves forward (note: we are not part of this project at all), but at the outset it is hoped that analyses like these will be employed by all parties to better craft the design process for this site. As always, questions, concerns and comments are welcome and appreciated!

2 views0 comments

Recent Posts

See All


bottom of page