Survival Game: Lives and the Lingering Effects of Flood Threats from Rivers in Kanagawa Prefecture

Last fall, we live in Metropolitan Tokyo area were hit twice by Super Typhoons, Faxai and Hagibis. In Kanagawa Prefecture, several were killed by landslides and flood. Tama River, marking the border between Tokyo and Kanagawa, flooded to kill a person in Kawasaki. Very fortunately, though, the banks of large rivers flowing in Kanagawa Prefecture did not collapse. It kept the damage from the typhoons somehow lesser in our towns compared with the other places like in Chiba or Nagano. In any case, it was a terrible experience. (For the photos about the disaster by Hagibis in Kanagawa, you can find them here, the site by Kanagawa Shinbun Newspaper Co.) 

A scenery showing how close it was for Sakawa River.

One of my seniors of Kanagawa Forest Instructors lives in Hiratsuka City 平塚市 along Sagami River 相模川. The bank of the river has been for her relaxed strolling. Then on 12^th of October, the city issued an evacuation order to her neighborhood because of the torrential rain, and the warnings from 4 dams, Doshi Dam 道志ダム, Miyagase Dam 宮ケ瀬ダム, Sagami Dam 相模ダム, and Shiroyama Dam 城山ダム, for imminent release of water to Sagami River. “You see, our 50-inch TV was brand-new, and it was on the first floor. So my husband and I brought it first to the second floor. Then, my son came home. We all three frantically moved our furniture to the second floor. Gosh, how heavy our microwave was! Finally, only the refrige remained. We discussed if we can carry it to the second floor. It was impossible. We decided to let go the machine and the food if the flood comes …” Then, they got into the car with few items of their belongings and headed for the designated shelter that was a nearby elementary school. “We found the place was damned full. No room was left for our family. In any case, the school was also near the river so that we moved on to another school that was in higher elevation. It was full again. We drove around for some time to find a safer place, and ended up in a school not in a walking distance from our home, but on a hill safely away from the river.” Her family stayed in the gymnasium of that elementary for the night of October 12th. They were distributed 2 blankets per person to sleep on a hard wood floor. “You see? I don’t know why but I grabbed my yoga mat when we evacuated our home. It turned out to be a jackpot-move. At least I could lay on the floor more easily. It was hard to sleep at that night. Many kids started to cry, and lots of elderly people had hard time to get up to go to toilet …” Thank God. Sagami River held up even with the discharge from four dams.

A goal post for soccer turned into a jumble of scraps
 thanks to the inundation from Sagami River last fall.

One of my pals as Forest Instructor is an officer working for Kanagawa Water Supply Authority 神奈川県内広域水道企業団. They are in charge of Doshi Dam, Sagami Dam, Shiroyama Dam, Miho Dam and water intake weirs in Sagami and Sakai Rivers. On that night they were on an emergency night shift. “You see? We did not want to discharge water but the speed of rising water level was abnormal. In the end, the gate of Shiroyama Dam was opened 5 minutes before the final warning was issued by the Prefecture. It was a close call. Thank God, Sagami River did not overflow … That was a super night.” Well, even though, the water of rivers in Kanagawa, Sagami, Sakawa, Tsurumi, et al rose quite close to the limit. My instructor senior went to the river bank several days later. “You see? Only the top 10cm of tall reeds kept its green, and the rest was covered by mud. In addition, quite many of them were completely beaten down to the same direction. The power of flood water was horrible …”

Could you see in this photo at least
 the water reached to that level from Sagami River?

The phot was taken on the bank of Sagami River early January.
 The vegetation was recovering to green,
 but those flatten muddy reeds tell the power of water.

It could be indeed miraculous the only death by flood of rivers in Kanagawa Prefecture was on the border with Tokyo. I’ve heard several communities received substantial damage in their rice paddies and tangerine orchards in the west of the Prefecture. Water of the rivers kept muddy for more than a month after Hagibis. Humans are still struggling to recover from the weather incidents. Having said that, to some extent, it would be an evidence the Prefecture does well to control rivers in the territory. Yeah, on October 13^th, a Rugby World Cup match between Scotland and Japan was held in Nissan Stadium even though the flood basin of Tsurumi River inundated the sports park surrounding the Stadium. It was thanks to a very good civil engineering design for flood control. Still, the power of Tsurumi River from 12^th of October was shocking. It extirpated many forests that existed along the Tsurumi River before Hagibis.

Sakawa River in the middle of November 2019.
 The water was still raging.

This photo of Tsurumi River was taken last August
 before super typhoons came.

This is for the same place as above
 after the typhoons in November.
 Frankly, I was shocked.

Then, what happened for wildlife along the river? In January, the waters of rivers have finally returned non-muddy. But the effect is still lingering. I knew there was a large Japanese walnut tree on a bank of Tsurumi River that was a home for lots of pacific reef herons. Then, the flood uprooted the tree, and these days I cannot find black herons there … The birds have received the damage too. Still, the place near Sagami-Ozeki Weir 相模大堰 on Sagami River has welcomed many migratory water birds as usual this winter. In the area, we have found accumulation of poops by Japanese raccoon dog family, and feces of wild Japanese hare. A peregrine falcon perched high-up on the power transmission tower near railroad bridge for Odakyu Line. Aster kantoensis, which is an endangered species (CR+EN in Kanagawa) were survived … Whatever happens by super typhoons, they are resilient at least for now. Is there anything we can do to ride on this strange series of weather with them together in 2020?

102140: This is also the photo of last August
in the bank of Tsurumi River where
 pacific reef herons returned before sunset.

Immediately after the typhoons,
 the tree itself stood with herons.
 But could you figure out
 the back of their nest is in a mess with uprooted trees
 and garbage from the river?

The city cleared the space for further riparian maintenance.
 No tree in January 2020. No herons.
 But could you see a Eurasian coot in the middle?
 Life goes on after the storm …

Poops of Japanese raccoon dogs
 on the dusty bank of Sagmi River this month.

Humans are busy to restore the bank for Sagami River.

I was a sort of impressed with these
 as hare was so resilient to leave their dropping here
 on the riverbed after the flood.

Sagami-Ozeki Weir in early January 2020.
 It withstood with the flood water
 which left such muddy vegetation and sandbags around.

But goose came to the Weir as usual this winter.

A nice couple of Eurasian teal,
 regulars for winter at Sagami-Ozeki Weir.

Somewhere in this photo,
 there must be a peregrine falcon …

If you find environmental issues in Kanagawa Prefecture, please make a contact with Kanagawa Natural Environment Conservation Center 神奈川県自然環境保全センター

657 Nanasawa, Atsugi City, 243-0121

〒243－0121　厚木市七沢657
Phone: 046-248-0323

You can send an enquiry to them by clicking the bottom line of their homepage at http://www.pref.kanagawa.jp/div/1644/

A Hidden World; From Ameyama Pass to Yushin Valley 雨山峠からユーシン渓谷へ

Although Kanagwa Prefecture is a part of Metropolitan Tokyo, we have one of the most secluded places in Kanto Region. It has a legendary beauty. The place is called Yushin Valley ユーシン渓谷. The valley is the narrow middle to downstream of Kurokura River 玄倉川 that starts from the east point of Lake Tanzawa 丹沢湖, at Kurokura 玄倉 community. Kurokura River runs to the east for about 12km. The scenery of Yushin Valley from the forestry road was/is gorgeous. In addition to seasonally changing vista of mountains, the water of Kurokura River is so pure. As it runs on the bedrock of white granite typical for deep Tanzawa mountains, Yushin Valley looks like a stream of sapphire blue in fine days. It is named Yushin Blue. People who saw the place told me, “You don’t have to go to Capri for Blue Grotto!” Wooooow. Unfortunately, the area is not possible to enter now.

At least on map, there goes a forestry road, named Kurokura Forestry Road 玄倉林道, along the Kurokura River up to the point where the valley diverts to Hohkisugi Stream 箒杉沢 and Nabewari Stream 鍋割沢. The access to Kurokura River by public transportation is from Odakyu Shinmatsuda Station 小田急新松田駅. We have to catch a bus to Kurokura operated by Fujikyu-Shonan Bus 富士急湘南バス. It’s about an hour bus-ride. From the bus stop we walk a forestry road, called Nakanosawa Forestry Road 中ノ沢林道, to the north for about 1 km to meet with Kurokura Power Plant #1 玄倉第一発電所. The beginning of Kurokura Forestry Road is about 2km north from the Power Plant #1, diverting to the east from Nakanosawa Forestry Road. Moving along Kurokura Forestry road itself was an adventure. It has 9 tunnels all of which do not have any lamp. Several of them have even cranks inside. The forestry road climbs up only slowly for about 300m with 12km. It may be long, but walking surrounded by gorgeous nature, Yushin Blue inclusive, was not so demanding for casual visitors. Say, if you’re a guy who wants to show how macho you are to your city-girlfriend in a stunningly beautiful scenery, the setting was perfect, with a series of pitch black tunnels … There was Yushin Lodge ユーシン・ロッジ at about 8km point from the beginning of Kurokura Road (; er, “there is,” actually, as the building is standing still). The Lodge was managed by the Prefecture. The Office used to allow people who reserved nights’ stay at the hut to drive to Yushin Lodge. The premise was popular among mountaineers as a base camp to the main peaks of Tanzawa, such as Mt. Hirugatake 蛭ヶ岳 (ASL 1672.6m), Mt. Hinokiboramaru 檜洞丸 (ASL 1601m) or Mt. Tanzawasan 丹沢山 (ASL 1567m).

There is a reason why the Prefecture constructed a forestry road in such a deep mountain. Before the diversion point of Hohkisugi and Nabewari Streams, there is a hydroelectric dam, named Kumaki Dam 熊木ダム. Kumaki Dam drops the water via underground aqueduct to another dam, Kurokura Dam 玄倉ダム / Kurokura Power Plant #2, which is in the middle of Kurokura River. At the Kurokura Dam, the water from the catchment area of Kurokura River is gathered. A part is used for electric generation at Kurokura Power Plant #2, and the rest is sent into another underground canal for electric generation at Kurokura Power Plant #1. The electricity produced in these two plants is sold to Tokyo Electric Power Company (TEPCO) and fed into the electric grid of Metropolitan Tokyo. So if you’re in Kanagwa, or Tokyo, you may use the power generated there now. It’s the thing of dam in Japan, and so, we can collect dam cards by visiting these places. (About dam cards, my post on April 19, 2019.) In addition, the place has legendary beauty! If you collect the dam cards, please take your selfie with the Kurokura Power Plant #1, and bring it to the Admin Office of Lake Tanzawa at Miho Dam 三保ダム (my post on April 19, 2019). Officers there will give you 4 cards at once: one for Power Plant #1, then for #2, Kurokura Dam, and Kumaki Dam. i.e. You don’t have to visit the power plant #2 and the dams. Why is this short cut? Because Kurokura Forestry Road is closed at the moment. There is no reason for human side to close Kurokukra Forestry Road, right? Mother nature thinks differently, perhaps.

Basically, the area of Kurokura River is a tricky place. Do you remember I told you a famous 1999 drowning accident of 13 people near Kurokura Dam? (My post on August 24, 2018.) It’s a really remote place. In 2006, the Prefecture checked the safety of the Forestry Road, and found large cracks in the third tunnel, named Aozare Tunnel 青崩隧道. The bonus treatment for the customers to Yushin Lodge was terminated, and the Lodge was closed in April 2007. New tunnel was excavated and opened in 2011 as New Aozare Tunnel, but the car usage of Kurokura Forestry Road was strictly limited for the holders of governmental permission … I think it made the legend of sleeping beauty Yushin Valley definitive … Then, on 17 January 2018, a troop of hunters who engaged in prefectural tasks of culling wild deer found another large fractures in the slopes along the route between tunnel #3 and #6. (I know this date, as one of the hunters is my Forest Instructor pal.) It snowed heavily next week. When people returned there after snow, huge landslides happened here and there, and the forestry road was completely blocked. The collapsed soil poured into the river so that, according to a person who went there, the Yushin Valley was not blue, but of whitish mud. As of January 2020, Kanagawa Prefecture sets up locked wire fences at the mouths of tunnels between New Aozare Tunnel and Tunnel #6. The beauty of Yushin Blue is off-limit for us …

Although currently we cannot approach to the middle to downstream of Kurokura River, we are able to enter, a sort of, the upstream of Kurokura River. How? Here comes Ameyama Pass 雨山峠 I reported the devastation last week. At least till the autumn of 2017, from Ameyama Pass to Kurokura Forestry Road, there was a relatively well-organized hiking road which ran from Ameyama Pass along Ameyama Stream 雨山沢 pouring in Kurokura River. We’ve been there last month to find almost all the hiking road is washed away up until the last few hundred meters of a metal plank path secured by bolts and nuts to the bedrock of Tanzawa. Below are the photos I’ve taken there.

Basically, the route from Ameyama Pass to Kurokura Forestry Road is
 on the riverbed of Ameyama Stream.
 We guessed the right-hand side of this photo was the trace
 where once a hiking road ran.

So, there are lots of “ruins” like this, dangling from the steep slope.

Still some installments are still working. Thank God.

The scenery tells why there is no route anymore here …

Smaller dry valleys tell us eloquently what happened.

Hmmmmmmmmm.
 Debris flow will happen again, and again, don’t you think?

This precarious red ribbon shows we’re on the right track.

This section of the route has a better condition.
 I was amazed water runs over the huge white granite.
 The bedrock remains, really.

Almost suddenly, a metal plank path appears. Strange …

Kurokura River is over there.

The route from Ameyama Pass joins with Kurokura Forestry Road at Ameyama Bridge 雨山橋. We proceeded further on Kurokura Forestry Road to Yushin Lodge … I think there have not been many people entered there. The Forestry Road has lots of collapses so that we did a bit of rock climbing in order to progress. Although the remnants of the road are paved, they were buried by thick piles of fallen leaves. Many dry valleys along the road were filled with large debris flow covering the forestry road. We glimpsed the entrance to Yushin Lodge across Kurokura River, and returned to Ameyama Pass due to time constraint. (Remember? Walking the route via Ameyama Pass after dark is suicidal.) The upstream of Kurokura River has a wide riverbed owing to frequent and massive debris flows. It gives us a feeling of “wide open space,” which is actually not at all safe. Large bridges and weirs were standing. I found them a sort of fruitless human struggle … It was the end of autumn. We met many large mosses that can be seen only in deep mountains. The whole landscape was so serene and beautiful …

At the crossing of
 the route from Ameyama Path and Kurokura Forestry Road

Ameyama Bridge is over there.

We recognized lots of footsteps of deer and large mammals on the road.
 It was paved route, but the sandy debris covers the road.

To Yushin Lodge

The collapsed Kurokura Forestry Road

Another collapsed part.
 Huh, it takes an effort to make this route passable again for cars.

The debris flow is covering …

Hmmmmmmm

The bridge to the entrance to Yushin Lodge.
 The weir over there is standing.

Don’t you think it’s beautiful?
 The forest over there is designated as
 one of the best 50 forests in Kanagawa Prefecture.

Kanagawa Prefecture is having a hard time for managing Kurokura and Kumaki Dams both of which are now beyond the locked-off area from Kurokura community. The only way for the officers to go there is on foot via Ameyama Pass. The Office has asked Kanagawa Forest Instructors to give them any information about the access to the area. The senior Instructors are presuming the Prefecture could not leave Kurokura Forestry Road as such because of hydroelectric power generation. At the moment, the prefectural government plans to start repair works this spring, and to open the entire Kurokura Forestry Road by the end of March 2023. Until then Yushin Valley remains as an inaccessible secluded place in our neighborhood. I’m just waiting for the time we can go there more easily. But, if such days come, those lovely large mosses would be gone by lots of tourists. Sad. Which is better in the end?

Climacium dendroides

If you find environmental issues in Kanagawa Prefecture, please make a contact with Kanagawa Natural Environment Conservation Center 神奈川県自然環境保全センター

657 Nanasawa, Atsugi City, 243-0121
〒243－0121　厚木市七沢657
Phone: 046-248-0323

You can send an enquiry to them by clicking the bottom line of their homepage at http://www.pref.kanagawa.jp/div/1644/

Inshallah redux; the southwest slope of Mt. Nabewari to Ameyama Pass after Typhoon Hagibis 雨山峠

For about a month, I have been hesitating if I post today’s topic ... I’ve decided to go ahead. This week, I tell you how the southwest slope of Mt. Nabewari 鍋割山 (ASL 1272.4m) is now, after Typhoon Hagibis. Mind you, at the moment Kanagawa Prefecture strongly discourages anybody to go there due to the devastation by Hagibis. So, this post is NOT for introducing the hiking course. I WILL NOT tell you the itinerary, but just show you how the situation was in early December before winter snow. Next week, I tell you my tiny experience in Yushin Valley ユーシン渓谷 that now is practically off-limit for casual visitors due to winter collapse (more to it next week). We Forest Instructors of Kanagawa Prefecture are worrying the same should happen in the southwest slope of Mt. Nabewari during this winter. If not, the next big typhoon will surely bring further destruction. It’s not a place for somebody new to Tanzawa 丹沢 to enter. I’ve been there with my senior instructors as a part of duty to make it sure how bad the situation is in order to inform visitors. Several forest Instructors, including a veteran ranger for Akaishi Mountains (aka Southern Japanese Alps), know the place well for decades. Actually, the southwest slope of Mt. Nabewari is defined as Yadoriki Water Source Forest やどりき水源林 so that it’s the area Kanagawa Forest Instructors are supposed to know well. Inshallah. The scenery was awesome, honestly.

Having said that, rough sketch of the itinerary is like this: it starts from the main gate of Yadoriki Water Source Forest, crossing many times Yadoriki Stream 寄沢, and ends at Ameyama Pass 雨山峠. The route traverses the notorious “Collapse in Hell” slope 地獄崩れ which has become more hellish by the typhoons. Moreover, it’s extremely difficult to figure out the routes now due to frequent landslides after the storms this fall. In any case, typhoon or not the route is well-known among Japanese alpinists as one of the most dangerous routes in Tanzawa mountains. Many people died, or went missing. A husband who returned to pick up an item left in the picnic bench of Ameyama Pass has not reunited with his wife since October 2018. These 3 months, there are several reports for encounters with bears in the route. You’ve got an idea, I hope.

Yet, if you do want to try, the things you MUST do are

1.      Find people who know the place damned-well, and say OK to go there with you.

2.      Choose the season of your visit: end of fall or late spring will be the best. For both times, the infestation by vampire leeches would be minimum. The weather could be relatively stable with fewer rain.

3.      NEVER enter there when it rains, or a couple of days after the rain. The route shall be deadly slippery, and you can put your name in the list of deads who tripped over the scree.

4.      Be well-equipped. Real climbing shoes and good gloves are the MUST-HAVEs. Also enough food, water, emergency kits, et al.

5.     For this route, VERY GOOD MAP, COMPASS, and HEAD LAMP WITH ENOUGH BATTERY are also indispensable. It’s so easy to lose the way here even for veterans. Those gadgets are handy when emergency happens. Imagine you lose your way, and find yourself alone in a completely dark deep mountain … thus for the head lamp. If you have iBeacon or cocoHeli, DO carry them. 

Now here are the photos how things are over there.

Yadoriki Stream has changed its riverbed completely. The course of the stream itself has altered drastically, and the nice points for crossing the stream have gone. We have to search for the places to get across. Forest Instructors worry those possible new routes could tramp rare plants that were once in shielded corners of the forest. Let us see carefully what happens to them …

Those roads which was once in the forest along the stream now look like a part of riverbed with trees sticking out of scree. It makes difficult to figure out the route. We searched the direction shown by a pink ribbon somebody left before us. There is no guarantee we can find the next ribbon soon, though.

Before the Collapse in Hell slope, there is a large landslide that destroyed completely a debris barrier for Yadoriki Stream. On the foot of it, there are piles of large trees with their roots sticking out to the sky. The entire grade broke down during the storms this fall. Here, we could figure out how thin the topsoil is in Tanzawa Mountains … We are sure, it will collapse further soon.

The “Collapse in Hell” slope is more hellish now with piles of logs on foot and more screes. It would be extremely difficult to traverse there if it rains, or immediately after rain. We were lucky.

There are several points where originally narrow plank path becomes thinner conduit precariously runs over slippery scree filled slopes tumbling down to deep valleys. To traverse such points we really had to go on all fours; and so, gloves are the MUST-HAVEs.

Strangely, the final stretch to Ameyama Pass kept its course as before the Hagibis. However, this is the area where many deaths and missings occur for decades. It’s simply preserves its trickiness.

Although this is very difficult place to enter, it is the only course currently to go to Yushin Valley as a day trip. I tell you my adventure to Yushin Valley via Ameyama Pass next week. I know you would ask “What is Yushin Valley?” Well, stay tuned! 😉

If you find environmental issues in Kanagawa Prefecture, please make a contact with Kanagawa Natural Environment Conservation Center 神奈川県自然環境保全センター

657 Nanasawa, Atsugi City, 243-0121
〒243－0121　厚木市七沢657
Phone: 046-248-0323

You can send an enquiry to them by clicking the bottom line of their homepage at http://www.pref.kanagawa.jp/div/1644/

Season’s Greetings from Adventure in Yokohama Citizen Forest

Sparrows in Yokohama is waiting for the spring to come on Japanese beech.

This tree always blossoms in late autumn, and looks like a cherry blossom. So I think it’s “Fuyuzakura,” Japanese beech. We’ve passed the winter solstice already, haven’t we? Spring will come soon. Or sooner because of global warming?