Omotehama excursion Report


Omotehama excursion



This excursion invited it in the CBD citizen network Kaifu meeting today.
We invite LEE doctor in charge of the ocean of the Biodiversity Convention secretariat.
Though, as you know, it was held in Aichi, in the Biodiversity Convention contracting party meeting, it was in what kind of problem by saying that the ocean was frightful, and it was the big agenda at the time, and after all we wanted to call directly, and an area invited it why it should have been said though, for example, with Aichi or activity such as the Omotehama or a Japanese citizen participated.


The Omotehama is right the place that is the best to know the element of the various seas concerning the dynamic open sea and a big river and peninsula.
Therefore an Omotehama network puts up a plan to say to have various people watch this Omotehama as a sandy beach on behalf of Japan at the time of COP10.
Therefore it may be said that the Omotehama network wants to do some kind of pushes to have you take up a problem and the possibility that such a sandy beach holds in the marine agenda in COP10 with wanting the LEE doctor who was able to come by the invitation of participating CBD citizen network to make a preliminary inspection of Omotehama somehow.

*We pass through the Shiomi Hill tunnel



It is right a place called the Shiomi Hill here concerning a slope to see the tide.
As a matter of course, Longshore currents or an ocean current are strong reason, but, in the Pacific, there is the rip current that is very strong in this offing.
An ocean current is the rough shore.
The weather is very good, and a good wave stands today.
A low-pressure sodium lamp is used, and, as you know, the sea turtle is sensitive to light, but, in the Hamana bypass, the consideration that orange light does not give stimulation to a sea turtle is done.
We think that we understand the way of the use of the shore when we have you watch the left hand and understand a seamark with a beachline.
The lower area of the bus just thinks it whether it is a dune now.
The Hamana bypass is very scenic when we look down at the shore from high bass because eyes become higher.
We see a bow-shaped shoreline of Atsumi Peninsula forward.
We are veiled a little, but it is highest peak Koshido Daisen of Atsumi Peninsula to be seen in the point of the peninsula.
There is an Irago cape over there, and, in the other side, there are stage of the sound of the sea breaking on the shore of that famous Yukio Mishima and Kamijima where it was.
There was just just a landing trace turtle truck of the Loggerhead turtle.


LEE doctor

Generally Loggerhead turtle comes in what time and what time does come back to the sea in?



The landing begins at night around 9:00, and the peak spreads out until around 3:00 since middle of the night 12.
Because we become slightly spirited, and it is approximately brightness in the daytime early in the morning at 5:00 from around half past 3, the shore understands that a sea turtle is active in the time when there is really a few it.
The explanation of the document
We perform Conservation of beach activity for the winter season.
Recognition by consistency of the protection activity of the sea turtle is high, but performs it for around six years so that it really preserves the habits in good condition to improve the base environment of the sandy beach that it is the most suitable way.
The Sand Fence of the cover is very classic Conservation of beach activity.
Because it is the method that it collects sand in, we cannot expect the particularly lasting effect and immediate effect, but, with pleioblastus simonii growing wild in the shore, we study it what kind of influence this Project has on the laying eggs of the sea turtle because Toyohashi-shi performed "eco-coast Project" in form to consider the laying eggs of the sea turtle in the active place in 2006 to sip an evaluation of this shore construction.
Please talk to Mr. Aoki about a part of the surveying of this inside.



We begin with May, 1999, but measure the form of the sandy beach at around three places of shores of Toyohashi.
At the beginning of 1999, we did it once a month, but a change was intense and understood that we said that a sandy beach was not arrested in this very much.
We understood that the change of about one year was suppressed if we measured it once a week.
Because they begin to do it, and around 11 years already pass, considerable data collect.
When take the distance from a threshold simply on the cross axle between time, and take it though there are not many meanings to length because is the shin, the distance from the threshold which there is at the distance in a vertical axis; such as (the right figure) was changed.
As for understanding it, the width of the sandy beach understood that there was a long-term change slowly from now on while changing at 40m from about 30m.
Generally it was about time when a wave grew big in autumn, and a sandy beach became small and understood how wide its change was for a cycle that we came back in winter.
Then a straight line is pulled, and what we were surprised at a little becomes the upward slant to the right, but this is a trend.
We knew ten years when we looked at this trend only after we did it, but understood that a sandy beach gradually opened.
This neighborhood was case that a sandy beach got sterile, but, in fact, the area of Toyohashi was by little, but by around 1m a year understood that we said that local that a sandy beach spread out.
Unevenness becomes intense whether there is a place, and it is these past dozens of years when a sandy beach becomes very wide with a place becoming small when we look altogether.
Therefore the beach gets sterile in the whole, and it is the reason why a problem does not happen.
We understood that there was good sandy beach environment for reason to have unevenness on by various human activity about Toyohashi.
Because we understood that we did not need the block, and Toyohashi removed a block in this sense and thought whether it was for the movement that it was said so that a tortoise was gone up to the sandy beach, when case to accumulate such data was the case which after all was important, it seemed to be said and thought that we looked at the shore with such eyes.


Circulation and the exchange of the opening type shore that is a wide area.


The excursion left Toyohashi Station in a Sun simple melody of the summer and aimed at the Hamana bypass of the Shizuoka side that expected straight Atsumi Peninsula from the west along National highway No. 1.
The shore along the national highway is the shore where a sandy beach developed like Omotehama.
A seamark is shown in the coast by drifting ashore such as the eelgrass and can observe the good point of the shore of the wide area opening type.
We go ahead approximately approximately 20 kilos, and Araimachi equal to Hukou of Hamanako turns it down in Imagire inlet.
We see Atsumi Peninsula from Ohashi, Hamana in a flow of the drift sand which just flows through the coast and the course.
The coast that is a wide area can confirm the scene surveying this Atsumi Peninsula and can grasp a beachline continuing west for a long time, a beach step, a sandy beach of the runnel (a tide pool) rear, the exchange of the material of the opening type coast called the dune and circulatory environment.
As an example, various materials are carried with the earth and sand which flow from the land area into the sea by Longshore currents when we arrest such material exchange and circulation to be performed on the coast, and the material carried to the shallows including the coast sandbar of the いそ wave Zone is made disturbance, eutrophy by a surge and produces algas by light of the sun in large quantities.
And it leads to a microbe ring to eat an alga.
Furthermore, it is washed ashore on the coast by nearshore current, and seaweed and a fish, the corpse including the bird carried to the sandy beach are broken down by the crack creature (sand hopper) of the sandy beach.
Because the sandy beach Coast that was this wide area confirmed the circulation of the material and a thing or the state that we changed with the earth and sand how, we left for the Shiomi level of the Kumi Hara shore of Tahara-shi (Shiomi hill in the fishing with a seine net-fishing) by this excursion and observed the whole view of the Omotehama coast.


The coast and source of a river cultivation forest

We can confirm the whole view of the Omotehama to look at from Shiomi stand of Kumi Hara at the time of the ebb tide from the beach to the shallow coast sandbar.
From these prospects, Kamijima and the scene floating to Ohashi, Hamana of the Imagire inlet which is Hukou of Hamanako which we surveyed to the east until a while ago, Koshido Oyama which are the highest mountain of Atsumi Peninsula in a west end, the Irago water service far range, and we are endless, and the east and west can command a whole view of a beachline of the continuing Atsumi Peninsula Pacific coast for Pacific coast 180 degrees.
Therefore it is beachline and seamark and opening "shore wave zone" from the coast sandbar to be characteristic.
Coast sandbar develops in "shore wave zone" of the Enshu rough sea coast that is a wide area very much.
Nearshore current surrounding this coast sandbar promotes exchange and the circulation of sand and various materials lively.
Furthermore, it springs out so that it is likely, and, in the foreshore that a sandy area gets wet when we observe a foreshore carefully, and looks black to you, an obi is recognized.
A small water vein flowing from the hill of the rear spreads among these, and a basement is deep, and groundwater drifting ceaselessly bleeds at the coast.
A gush tongue is done like a design continually from the sandy area and forms the aspect-like material exchange of the shore which is a wide area.


A laurel forest Zone ranges on the hill, and fulvic acid including the iron content spreads among such a water veins, and it is progressed in the sea by the humus.
The laurel forest Zone of the hill has important work to supply nutrition in the sea as the source of a river.
(source of a river cultivation forest:)


We are big, and the water vein along this fish charge account forest) coast contributes to the exchange of the material with the class of small creatures hiding behind in the gap of the sandy beach.




Shogo Arai (Manager of company underwater scene research institute)

explained the source of a river cultivation forest from Shiomi stand by the excursion.
The excursion advances more to the west, and it is come by the flow of the earth and sand by the Akabane fishing port east bank equal to the latter half.


It is explanation by an erosion problem from a point of view integrated at Atsumi Peninsula that is the west end in the Enshu rough sea from the Tenryu River that is the source of supply of the earth and sand from Professor Shinichi Aoki who has been studying the observation of the Akabane fishing port for many years as sand-flow system here.
As a result of we installed a structure including the offshore breakwater for the thought of each management ward from the upper reaches of the river to the long shoreline, and having coped, we have finished such a distorted shoreline.


The sandy beach shore which deteriorated becomes the weak environment as natural environments on the disaster prevention side.
We make use of a dynamic effect of the sand, and it becomes the future problem to aim at the integrated management not to disturb a flow.


The east of the Omotehama advanced from Hamanako Hukou to the west and, in the shore of the tendency to erosion, observed the characteristic of the wide area opening type sandy beach shore with the flow of the earth and sand in the Akabane fishing port east bank in the tendency to sedimentation.








We had a long sandy beach, dune which dismantled the small river which flowed from the laurel forest Zone of the rear, a spring under the ground, a wrack and showed that exchange and the environmental maintenance to continue of the sandy beach shore which circulated were important to the coast, maintenance of the marine biological diversity in the aspect domain that was a function wave Zone and a wide area as the circulation pump which ranged.


In the meeting after this excursion, this knowledge was made use of.

For Top