Small wonder: Haruhino-Kurokawa Forest 2

 

The lab by Prof. Yasuo Nihei for Tokyo University of Science is studying concentration of microplastic contamination at different points of river systems in Japan. They studied rivers in Kanagawa Prefecture as well. The researchers collected 1m3 of water from each point, then using their special tools counted the number of microplastic particles. The result was in a sense predictable. Immediately before ending in the sea most Kanagawa’s rivers go through downtown areas of large cities. At that point, a river has collected garbage from its entire basin, and so the pollution becomes worse when the lab measures the contamination. That’s that. In contrast, the water source areas of Tanzawa recorded the minimum number of microplastic particles. Long live Yadoriki Water Source Forest!

Minimum microplastic count in Yadoriki Stream

Another interesting found was when a river has large basin of suburbs, the level of microplastic contamination can be serious. The case in point was Hikiji River 引地川 whose water source is Izuminomori-Forest (泉の森; my post on February 19, 2923). Immediately out of 42ha forest, Hikiji River is sandwiched by Atsugui Naval Air Facility of US Navy and heavily developed housing area. After saying goodbye to Americans the river goes on in the middle of suburbia and commercial farms until it ends at Kugenuma Kaigan 鵠沼海岸 seaside for Sagami Bay 相模湾. When we check Google map, the basin does not have a large mass of forest, but lots of small dots of “green” for gardens of detached houses. The level of microplastic contamination turned out to be the worst in Kanagawa Prefecture for Hikiji River. Nihei Lab checked the origin of plastics, and identified more than 50% of them were from artificial lawns made of plastics. Come to think of it, these cheap alternative plastics for organic lawns are regularly stamped, kicked, and pressured by pedestrians and vehicles. They’re rapidly worn out. Inevitably, the basin that is surrounded by green plastics of artificial lawns are covered by microplastic particles. When it rains, they are washed down to the river. Hikiji River becomes sewage for microplastics. Poor river …

A stream immediate to the water source of Hikiji River.
At this point water runs through Izuminomori Forest
so that the possibility for plastic lawn particles
 comes in is minimum.
It‘s a pity we cannot keep the condition.

In November 2021, Nihei Lab checked water systems in the City of Kawasaki for microplastics. Area-wise, the most contaminated point was at the confluence point of Yakami River 矢上川 and Shibukawa River 渋川 (or, I would say heavily constructed Canal) in the east of Hiyoshi Station, near Hiyoshi Campus of Keio University. It was in the basin of Tsurumi River. Checking Google Satellite Map, the basin of these two rivers is heavily populated downtown. Lots of plastic trash would pour in to the rivers. They eventually push up microplastic contamination of Tsurumi River. The lab also studied the area around Shinyurigaoka Station of Odakyu Line, which is in the basin of Tama River. Compared with the studied point for Yakami River, the area is more residential with a large golf course, university campus, and TV studios which provide more green in satellite photo. Moreover, the local shop owners of commercial areas of Shinyurigaoka area are regularly clean their area for customers visiting a comfortable environment. Unfortunately, the place was still contaminated, though not as for Yakami River. Moreover, the pollution was heavier for pure residential areas than for commercial areas (e.g. golf courses) or business premises (like shopping areas). In such neighborhood, the clean-up effort is completely entrusted with the homeowners of suburbia. Er, well … (; my post on November 24).

One of the forests in Shinyurigaoka area.
 It’s small, but maintains the remnants of
yesteryear’s biosphere for Tama Hills.
It’s completely surrounded by housing.

Nihei Lab also measured the contamination at the confluence point of Asao 麻生川 and Tsurumi Rivers. According to the YAMAP Basin Map, the basin for this point originated from the south slopes of Haruhino-Kurokawa Forest. With Google Map, the area is also crowded by housings but not as heavily as Shinyurigaoka area, or the basin of Hikichi River. For easy garden-maintenance, it would be understandable for homeowners in Kurokawa area also love to use plastic lawns et al, wouldn‘t it? Lots of microplastic could be found in the confluence ... Nah.To everybody‘s surprise, the river water from Haruhino-Kurokawa Forest はるひ野-黒川の森 has one of the lowest contamination of rivers in Kanagawa Prefecture, standing together with water source areas in Tanzawa.

Water source area for Asao River
in Haruhino-Kurokawa Forest

There would be many reasons why they are so. Yeah, rivers from Kurokawa Forest goes through housing areas before joining Tsurumi River. But the households in Kurokawa area include old families that have lived there for more than a century. Of course, there are lots of new comers in their neighbourhood. In the end, from Kurokawa Station to Shinjuku Station it takes only 30 minutes. Many urban commuters whould love to move in. But strong local tradition may have protected the enviroment from the invasion of plastic lawns. Veteran locals in Haruhino-Kurokawa area are the people who created volunteer associations managing the Forest. Their leadership must have done a very special thing. And their activies provided scientifically endorsed result for the environment. Wow.

When we enter Haruhino-Kurokawa Forest
from Haruhino Station, we first meet
with a ridge way running along Metropolitan Road 18
 that is the border between Kanagawa and Tokyo.
The ridge way is an old commuter route
carrying products of Kurokawa Area
to Hachioji or Edo (Tokyo) for centuries.
Now it is a nice strolling path for locals.

And the maintenance of this old route is done
 by local volunteers who invite mates
to do the weekend task.

Well-controlled undergrowth along the route.
Good job!

In the ridge of Kurokawa Forest,
there is one open space with benches.
From here to the south, or to the left of this photo,
is the basin for Asao River.
It‘s a good place to have lunch
if you spend your weekend in Kurokawa Forest.

To reach to the ridge,
we take this road climbing
from the bog for the water source.
It is well-maintained road easy to walk.
This tells the endeavor of volunteers.

Looking the basin of Asao River
from the ridge way of Kurokawa Forest.

So, if you‘re planning your Christmas holiday stroll with your loved-ones in Tokyo megalopolis area, please think about visiting Haruhino-Kurokawa Forest. The starting point is either from Haruhino はるひ野 or Kurokawa 黒川 Stations of Odakyu Tama Line 小田急多摩線. From Haruhino, please turn right at the corner of Buddy Sports Kindergarten located at the end of station square. Please go straight, and you‘ll find steps going up which is the beginning of the forest. From Kurokawa Station, please go first to Farmers’ Market Ceresamos, open 10:00-15:00. They have a good choice for veggies, garden plants, and fruits from local farms. They also sell tofu, fish and meat made in Kanagawa. The road runninng to the west from Ceresamos leads us to the an experimental farm of Meiji University. Along this road, on your right is the mass of trees which is Haruhino-Kurokawa Forest. We can meander into forest from whichever road goes to the north from the road. If you lose your way, just return to your starting point, which is within half-an-hour train ride to the downtown Tokyo. Not bad, huh?

Haruhino Station

The open space in front of Kurokawa Station

Ceresamos

Oh, I have to add this. One of those houses surrounding the forest is the parents‘ place for Takefusa Kubo, the midfielder for La Liga Real Sociedad, who is murmured to be the next Messi. The soccer clubs for kids around Haruhino-Kurokawa area are constantly created Japanese star footballers for Japanese National Teams. Kaoru Mitoma for Brighton & Hove Albion F.C. also spent his kid‘s days not far from here. Mini-footballers of the area are running everyday in their microplastic-free pitches near the Forest. It might be another miracle of Haruhino-Kurokawa Forest. 😉

The blue and white bldg. is
Buddy Sports Kindergarten near Haruhino Station.
In November, they were cerebrating
their teenage alumni who newly obtained
 seats for teams of J League.
The tradition continues ...

If you find environmental issues in the City of Kawasaki, please make a contact with 

Environment Bureau 川崎市環境局環境対策部環境保全課
1 Miyamoto-cho, Kawasaki Ward, Kawasaki City, 210-8577
〒210-8577 川崎市川崎区宮本町1
Phone：044-200-2516
Fax：044-200-3921 

30hozen@city.kawasaki.jp