A Quick Introduction to Outing to the Riverside in Japan: Play It Safe 101

It’s HOT! Basically Japanese summer is very humid, e.g. 80% or above humidity, always. This year, the dampness often dances with extremely high temperature, like 38 or 40C◦. I’ve heard a conversation, “Well Jakarta is far cooler now than in Tokyo, honestly.” OK, OK, OK. So, we in Megalopolis Tokyo are devising remedial measures to cope with the reality. Let’s go to riverside! Japanese culture has lots of traditional ways to summer with river. You may know tourists’ attractions like shows of fishing with cormorants 鵜飼 (for example, here or here), having banquets on houseboat (for example in Tokyo Bay, here or here), or watching fireworks on the riverside. Er, well, it would be nice to feel a breeze from a river during those shows, but they are (A) expensive, and/or (B) for you to cram yourself in a limited space of a city. Take Sumida River Fireworks Festival 隅田川花火大会; it attracts more than 1 million people within 2.5km² along Sumida River 隅田川. Looking up to see fireworks with 1 million people situating shoulder-to-shoulder in humidity 80% at 35C◦ would be … not for cool breeze, I guess. There is another up-to-date kind of summering with Japanese rivers. That is BBQ or picnic on the riverside in forests.

Having said that, strolling and having lunch on riverbed
 can be relaxing during spring.
 It’s a scenery along Arakawa River 荒川 in March.

But during mid-summer,
 rivers in the city cannot offer much retrieve
 compared with the streams in the mountain
 … It’s Tsurumi River 鶴見川 this august.
 The banks are deserted, aren’t they?

Kanagawa Prefecture 神奈川県 has many rivers with dry riverbed when weather is nice. So people go there with cooler boxes staffed with foods and drinks. We set up a tent for shade, and prep for a riverside party. Nice, isn’t it? Yeah, but before that, a basic info: Japanese rivers and riverbeds are the property of the government. The biggest or the nationally important ones are owned by the national office. For smaller ones, prefectural or municipal governments take the ownership. In any case, the national government delegates day-to-day management of the rivers to local governments so that local offices have actual jurisdiction over the usage of Japanese rivers. They are responsible for flood control and environmental conditions of the rivers. Inevitably, there are several protocols for picnic with rivers. Let me list them.

The riverbank of Sagami River 相模川 near Samukawa Water Intake Facility 寒川取水堰.
 Sagami River and its riverbeds are owned by the national office,
 and Kanagawa 神奈川県 and Yamanashi Prefectures 山梨県 are
 commissioned to manage it within each border.
 The Kanagawa Prefectural Office has built
 an athletic field-cum-retarding basin here.

1.     Not all riverbeds are safe.

It would be a common sense. Especially in Japan, many rivers are short and rapid with upstream dams for flood control. May be due to global warming, these several years we are having sudden and unexpectedly heavy downpours in deep mountains around such dams. A short and small river can quickly turn into a wide muddy stream and running down to the downstream riverbed within 10 minutes. The place you think is safe enough for picnic can abruptly be swallowed up by Tsunami-like river water, even under sunny blue sky. So,

A) Please check locals beforehand if it is safe for pitching a tent for your BBQ or picnic at your chosen riverbed. If they recommend not to, just follow their local knowledge.

B) During the consultation, locals can tell you if there would be emergency sirens or the notices issued by the authority when the imminent danger is coming. Please do take this information seriously and follow the local instruction if you unfortunately are facing such calamity. Where is the megaphone for the sirens? Where can the officers come to let you know the time to escape? Which direction is safe if the muddy water chases you? You must make it sure at least these points, and be ready for such contingencies.

One day, we’ve found trashes
 beneath Yadoriki-ohashi Bridge 寄大橋 in Tanzawa 丹沢.
 Disgusting … who did it?

And a week later,
 the riverbed beneath the Bridge was almost cleared …

We found only a chair at 10m below of the weir.
 The thing is,
 during that week no substantial rain came in Yokohama,
 and it was difficult for us to imagine
 Yadoriki River 寄沢 had such a massive flow
 to push down the garbage.
 Hmmmmmmmmmm.

2.     Don’t underestimate Japanese river.

A) Yeah, ours are tiny, but often rapid, or hiding swift stream underneath. These days, lots of city folks come to a riverside, having a beer party, jumping into a river laughing, and drawn dead due to the ferocious torrent. This newspaper article is one of the recent ones calling our attention to the issue. Be very prudent, please.

B) Tiny rivers in Japanese mountains are almost always surrounded by forests. In order to stop forest fires, unless the place is designated, fire is prohibited in all the riverbeds in Japan. You’d better check if you can BBQ over there, first. Otherwise, you’ll be charged by criminal offense.

A riverbed of Ushiro-zawa Stream ウシロ沢 running on the south-west slope of
 Mt. Nabewari 鍋割山 (ASL 1272m) of Tanzawa.
 Yeah, when it’s a fine day, the river width is not much
 but the water runs very rapidly.
 Moreover, tiny but high water falls
 join with the stream here and there,
 and we find lots of large rocks with sharp edges along the river.
 i.e. When it rains,
 this refreshing small flow becomes destructive torrent
 gouging out the porous soil of Tanzawa.

On the riverbed Yadoriki-sawa River 寄沢,
 any fire usage is prohibited.
 Instead, people can come for sun-bathing
 and have sandwiches.

3.     Often a nice picnic riverbed is attached to a business right.

A) The most obvious one is fishing rights. It’s safe to think all the attractive rivers in Japan are covered by fishing rights of some fisheries cooperatives. Do you know even the estuary of Tama River 多摩川 of Tokyo-Kanagawa is divided by the rights of several cooperatives who fish for Conger-eel, aka Anago あなご, for sushi? So, if you go fishing in Japanese river, please check first where to buy an appropriate fishing license. Otherwise, your deed can be a theft punishable by a jail-time.

B) OK, you plan to have a BBQ party on that riverbed. But is it allowed to do so? You see, if no one looks, weekend revelers can trash the place with garbage, play loud music without thinking the residents nearby, leave poops et al anywhere, and, for the worst case, invite crimes. So, municipalities often request local business to watch for the manner of visitors by giving them business rights on the riverbed. The nicer the riverbed, the more lucrative for business. Almost all the nice-looking BBQ places in Japan are covered by local BBQ proprietary these days. Before start a fire with your charcoal, you’d better know if it is OK to bring your BBQ gear to that riverbed. The place could be only for the customers who borrow such things from the vender situated nearby. Making trouble with them would be charged by an obstruction of business. 

A sign of selling fishing license
 for Hinata River 日向川 on the foot of Mt. Oyama 大山 (ASL 1252m).

Doshi River 道志川 is famous
 for its large choices of camping and BBQ sites.
 (For Doshi River, pls see my previous posts in last January and February.)
 It’s Lower Doshi area,
 Aone community 青根 of Kanagawa Prefecture,
 where we can recognize the camping business
 down there along the river.

Huh, you may think these are all the cumbersome rules for your summer ... er, well, it’s your choice to think so … One anecdote. On August 13, 1999, there were lots of campers who used the informal riverbed of Kurokura River 玄倉川 pouring into Lake Tanzawa 丹沢湖. There suddenly came typhoon rain around 15:00, and the water level of the river got rapidly higher. Upstream is KurokuraDam 玄倉ダム as an intake weir that protects Miho Dam 三保ダム of Lake Tanzawa, one of the main water sources for 9 million people in Kanagawa Prefecture. The authority saw the danger of an outburst in Kurokura Dam and decided to open the gate if the time comes. From 15:20, the dam officers ran around the area calling for evacuation, but 21 people from Yokohama poo-pooed the warning and stayed on the riverbed. At 20:06, the dam asked local police to enforce the evacuation of those “remained,” and at 20:20 Kurokura Dam reached the limit to open the gate. At 21:10, their camping site became a sandbank within a violently muddy stream that prevented the police, firefighters etc. from reaching to their place. After midnight, the main mass of the typhoon clouds hit the area, and August 14 was the day of rescue and search by the emergency rangers of the Japanese Defense Force in the storm and the angry river. 13 dead bodies of them, including a 1-year old baby girl, was found in Lake Tanzawa. The authority even opened the gate of Miho Dam to find them, which was criticized because it could cause water shortage among 9 million people if the weather condition was worsened. Not much sympathy for those campers was found in the public.

… so they tried to drain the Lake Tanzawa
 for finding a body of a baby …
 Looking Kurokura River joining with the Lake Tanzawa,
 at the bottom of this photo.

In Yamakita Town 山北町,
 there are wide riverbeds
 in the downstream for Miho Dam in Sakawa River 酒匂川.
 No locals stay there for a long time.
 They know it.

Happy summering with Japanese rivers! Take care, and be prudent. Oh, yes, please don’t leave any garbage after your picnic or BBQ. 😉

The office of Kanagawa Prefecture which deals with the issues of rivers is

Division of Rivers, Prefectural Land Development Bureau 

神奈川県土整備局河川下水道部河川課
1 Nihon-Ohdori, Naka-ku, Yokohama, 231-8588
Phone: 045-210-1111
Fax: 045-210-8897

http://www.pref.kanagawa.jp/docs/f4i/index.html