Cherry Blossoms along the Shore: drought in Kanagawa Prefecture, spring 2026

 

Cherry blossoms! On April 1, Yokohama Local Meteorological Observatory announced its indicator cherry tree reached full blossom. Since then, we have a couple of days for spring storm, but at least around my neighborhood they keep their best. Hurrah! They will be so beautiful even when they are scattering. I hope a couple of more days left for us to steep in their ephemeral splendor … That’s said, something strange is happening. For one thing, the Meteorological Agency announced their weather forecast for this week: it’ll be warm days including several “hot days” with the temperature at the level of June. Their next 3 months’ forecast also says “The average temperature in Kanto Region will be high, and rainy monsoon season could start earlier than usual.” Well, do you remember my “prediction?” Soon after cherry blossoms, summer will come.

The early coming of monsoon season should be welcome. Actually, this winter was so dry in the megalopolis Tokyo area. Kanagawa Prefecture was not an exception, nor Yokohama. Our reservoir lakes for water supply remain in critical condition. As of April 4th, the entire water storage rate for Kanagawa’s main water system, i.e. Sagami and Sakawa River Systems, is 39%. It’s after more than 2 weeks of on-and-off rainy days. The worst is Tsukui Lake with Shiroyama Dam (; my post on Oct 20, 2017). The lakeside Prefectural Park, Tsukui Shiroyama Park, is famous for its cherry blossoms. But … look.

When a reservoir is like this, so is upstream area. This is the recent Yadoriki Stream. The comparison tells obvious: water level is low.

At the end of March 2026.
Right bank is dry enough to become grassland.

Yadoriki Stream in standard March

Yadoriki Water Source Forest is for Sakawa River system whose reservoir lake, Lake Tanzawa, shows 46% of water storage rate, or 51% of average year on April 4th. Tsukui Lake, a reservoir lake for Sagami River, shows 16% of storage rate or 21% of average year. i.e. Yadoriki Stream has more water than the other water source forests in Kanagawa. It’s scary. Kanagawa Prefecture and Tokyo Metropolitan Government have a water sharing agreement, and in normal times the Prefecture diversifies 220 million m3 water per day to Tokyo from Sagami River. Since last month, Sagami River could not continue this, and the supply to Tokyo was reduced to 110 million, i.e. halved, per day. The rainfall from mid-March has not yet let reservoirs recuperate from the drought.

The water level immediately after
the water gate of Shiroyama Dam.
Could you see the water level is so low?

Water source area is like this, and so is the downstream, i.e. Yokohama. We Niiharu Lovers worry if this spring frogs have enough water for their eggs. Next to Yatoda rice paddies in Asahi-Yato of Niiharu, there are two small ponds. They normally hold water for gelatinous frog eggs. If it’s tube-like, they are eggs for toads. If they are foamier, they are for Japanese brown frogs. This year, none. Reason? Both of these bonds are dried up. Frogs need water from February to March for their tadpoles. If there is no water, they do not lay eggs to begin with. “It’s sad.” “Yes. Oh, I’ve found some eggs in ponds next to Ikebuchi Open Space.” “Me too! They are brown frogs, aren’t they.” “But you see? The other day, I’ve been there in dusk and heard an owl hooted in a tree over the pond.” “What!? They are eating eggs and tadpoles.” “Oh yes.” Survival of the fittest. This is a harsh year for frogs in Yokohama.

Dried up

From rice paddies another stream goes to
the (artificial) pond next to Niiharu Community Centre
 in Satoyama Park.
It also has poor level of water.
As the pond in the park is man-made,
it keeps water somehow. But …

Tadpoles in Ikebuchi pond.

If monsoon comes earlier than usual with enough rain, it could give some respite for our water system. Yet, volunteers who nurture Yatoda rice paddies in Niiharu are seriously worrying the prospect of this year’s rice harvest. I guess it’s not a problem only for amateur farmers in our community. With soring energy cost (i.e. it’s more costly pumping from agricultural waterway), low or none water level is worse for agricultural production by pros. Last year’s harsh summer yielded poor crop of potato and onions in Hokkaido, and the cost of these is shooting up now in supermarkets in Yokohama. Let us keep crossing our fingers as the situation improves and we have sufficient water supply this summer. God willing …

Small flow for
Asahi-yato rice paddies this March.
Correction: No flow.

The flows from Niiharu Forest gathers in Umeda River,
then to Tsurumi River.
Inevitably, the water level for Umeda River is low now.
 It would be good news for Egretta garzetta
to procure meals in Umeda River. But …

If you find environmental issues in Kanagawa Prefecture, please make 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/