Earlier this week, I caught up on last week's blog post with my first report from last weekend's Cycling Embassy of Great Britain's AGM in Cardiff (with me so far?) This week, I continue with a look at the Greener Grangetown project.
Grangetown is a ward of Cardiff right in the south of the city and is largely bounded by the River Ely, River Taff, Cardiff Bay and railway corridor. Very roughly, the area is split between residential and commercial development.
To the east of the ward along the River Taff, the Greener Grangetown project completed in October last year, was a £2m investment partnership between the city, Welsh Water and Natural Resources Wales to better deal with stormwater in the area.
The previous situation saw stormwater going into the local combined sewer system which is pumped 8 miles to the nearest treatment works whereas the recently completed scheme deals with the stormwater at source by intercepting it with rain gardens which eventually discharge directly into the adjacent River Taff.
This is not to say that that a flooding risk is being added to the river because the whole idea of rain gardens is that they hold stormwater and allow it to slowly infiltrate into the ground or where the ground is too saturated or cannot take flows, they hold the water until after the storm event and so smooth the outflows.
Rain gardens also take water out of the system naturally with their planting through evapotranspiration. The other clever thing is that biological processes within the planting structure can also break down the oils and nasty compounds which can be found on the road surface as a result of motor traffic use.
On the ground, there are rain gardens of all sorts of sizes, from the small on street corners which also help keep parking away from junctions,
To the large which repurpose large areas paved as part of historic filtered permeability works, although the entire project area is not fully filtered.
There are a number of side streets which are curiously wide such as Abercynon Street (below). The side streets have central reservations which were previously just paved and parked over. The redesign has changed these paved areas into rain gardens, while retaining some parking (and there are lots of people parking in this area);
The other interesting thing about the project is that it has what is claimed to be Wales' first ever "bicycle street" along Blaenclydach Street and the Taff Embankment, essentially providing better space for the Taff Trail cycle route;
The layout has a central strip of imprinted asphalt to give narrow traffic lanes which gives information to people cycling that they may take the lane and that drivers should cede priority. This is not backed up with any legislative power, it's purely through design.
We visited twice over the weekend and for the most part, drivers seemed to understand how the street worked and when they did feel the need to overtake (despite the 20mph speed limit), most did so safely. I would say that cycling here did feel safer in a group and without traffic flow data, it's hard to comment on the appropriateness of the layout - certainly the driver in the photograph below didn't fancy hanging about and overtook dangerously.
I think that to truly create a bicycle street, more work is needed to get rid of through traffic because not only the spine of the scheme along the River Taff is unfiltered, a number of the side streets are also unfiltered. A bicycle street really needs to have cycle traffic in excess of general traffic to work properly.
The north end of the Taff Embankment is accessed through a signalised junction which is perfect for getting people into and out of the potentially filterable area. The plan below shows the scheme area bounded in green, the signalised junction at the top circled in purple and the unfiltered streets circled in red (there are private alleyways, but these are gated);
The layout of the streets would make it very easy to complete filtering with just 2 or 3 other treatments. My personal feeling is that the Taff Embankment needs filtering as it does present a nice straight run for drivers which is (I think) the reason for putting in road humps across some of the junctions - and filtered would have been cheaper than humped junctions;
One other little thing which came up on the visit was a proposal for a crossing over Penarth Road which runs to the north of the area. The proposed scheme has the a parallel zebra crossing to the east of the junction with Blaenclydach Street which would help cross the road and connect with the already filtered Dinas Place opposite;
The photograph above shows the view from Blaenclydach Street - the crossing would be to the right of the junction. The obvious answer here would be to filter Blaenclydach Street and have the crossing centralised to meet Dinas Place as I have roughly sketched here;
The other benefit of filtering here would be to remove traffic from the junction of Blaenclydach Street and the Taff Embankment which is currently an apparent conflict point - the Taff Embankment has to currently give way to Blaenclydach Street which creates the issue.
It's a fantastic project from the point of view of storm water management and the bicycle street concept is good, but to be a truly great scheme in terms of active travel, I think there needs to be that final push to exclude through motor traffic. Who knows, the idea might catch on!
Greener Grangetown is impressive, just look at these statistics;
- 42,480m² of surface water being removed from the combined waste water network (the equivalent of 10 football pitches).
- An additional 1,600m² of green space (the equivalent of 4 basketball courts).
- The creation of Wales’ first ever ‘bicycle street’ along one of the busiest sections of the Taff Trail Active Travel route, slowing traffic by design and improving conditions for pedestrians and cyclists.
- Increased biodiversity – 135 new trees and thousands of shrubs and grasses planted.
- Creation of a community orchard.
- 26 new cycle stands.
- 12 new litter bins.
- 9 new seats and benches.
- Increased resident-only parking spaces.
Arup was the scheme designers and GreenBlue Urban were the specialist suppliers for the water management systems.
I shall leave you with a film of what it's like to ride around the area and next week, there will be a third and final Cardiff post.