MIT Japan 3/11 Design Workshop / Summer 2011
Miyagi University / Keio University

WEST VALLEY | Utatsu (Minami-Sanriku, Miyagi)+ Although the West Valley [A] is not the major transect cut through Utatsu, its complex geological conditions demostrate the relations between
nature and humman intervention in the tsunami. The transect begins fromthe river edge, through the JR embarkment, and extends into the west valley. Before reaching the farmlands in the valley, a secondary transect [B] isbranching out across a kindergarten.

[B][A] [+ TRANSECT | WEST VALLEY
380 mDescription(i.e. slopes, vegetation zones vs. urbanized, etc.)

Inventory along Transect

3B / Transects
through the Site

Site Analysis]
Approximate Scale

01.5

37.5 km

WEST VALLEY | Utatsu (Minami-Sanriku, Miyagi)
ON SITE | TRANSECT [A]Section A

Section B

MIT Japan 3/11 Design Workshop / Summer 2011
Miyagi University / Keio University

WEST VALLEY | Utatsu (Minami-Sanriku, Miyagi)

10m

TRANSECT [A] | LAND FORM & WATER

Concrete surface performs badly in keeping water.
Comprehensive drainage system is required .

10m

Masonry surface with soil infill reduces the water
holding capacity.

Soil surface has strong water holding capacity.

3.11 Tsunami

Rainwater from mountain

River (-3 m)

Open air channel (- 2 m)

Catchwater (- 1.8 m)

1. Engineered embarkment

Description(i.e. slopes, vegetation zones vs. urbanized, etc.)

Along the transect A of west valley, the land formchanges from the engineered embarkment at riverend to farming soil on the other end inside the valley. In between there is a JR embarkment, whichinterrupts the transect continuity.
In addition, the water system is also changed fromengineered concrete channel, catchwater and traditional irrigation channels.

2. JR Embarkment

Inventory along Transect- River embarkment- Open Air water channel- Engineered slope retaining structure- JR Embarkment- catchwater- Trees- Cultivated farmlands- Rainwater reservoir

Irrigation channels (-0.5 m)

3. Cultivated farmlands

Site Analysis

3B / Transects
through the Site

Due to different in landform and water system, thetransect has dramatic difference in term of damages
and post-disaster conditions. The area with engineered
concrete land surface suffered from most serious damage, However, the cultivated farmlands iwith soil landn the valley has least damages. One of the reason is thesoil surface has better water holding capacity.
Approximate Scale

MIT Japan 3/11 Design Workshop / Summer 2011
Miyagi University / Keio University

WEST VALLEY | Utatsu (Minami-Sanriku, Miyagi)

TRANSECT [A] | LAND FORM & WATER
3.11 Tsunami level (+18 m)

Concrete Retaining : Provides protection to prevent slopes from erosion ,but its low wall porosity requires intensive drainage for rain

JR Embarkment (+8 m)

45o60oCatchwater (-1.8 m)SECTION ADescription(i.e. slopes, vegetation zones vs. urbanized, etc.)

Inventory along Transect

Site Analysis

JR underpass: Becomes a by-pass for water when tsuinami came. It created a severe flush with high water velocity.

3B / Transects
through the Site

A catchwater system, about 2 m wide and 1.8 m deepis used to collect rain water from the valley and slope.
Due to its materiality of concrete and engineered
strength, the damage is minimal. The concrete JR underpass also was preserved well after tsunami.

Approximate Scale

MIT Japan 3/11 Design Workshop / Summer 2011
Miyagi University / Keio University

WEST VALLEY | Utatsu (Minami-Sanriku, Miyagi)

10m

TRANSECT [A] | JR EMBARKMENT & VEGETATION

10m

Tree by salinated by seawater

Concrete retainment only protects parts ofuphill vegetations

The concrete underpass, below JR, became the weakest point during tsunami, vegetationand trees are seriously damaged by severe flush passing through3.11 Tsunami
3.11 Tsunami level (+18 m)
Salination level (+1.5 m)

1. Engineered embarkment

2. JR Embarkment

3. Cultivated farmlands

TRANSECT | WEST VALLEY
Description(i.e. slopes, vegetation zones vs. urbanized, etc.)

The damages and salinations of tress was most serious nearby the JR embarkment underpass during
the 3.11 tsunami. These damages indicate a directconnection between the JR embarkment and its
context

Inventory along Transect

Site Analysis

Originally, the JR embarkment is engineered strongly as
an infrastructure to support the JR railway. In addition,
it could function as a dike to protect the inland valley.
However, th tide of tsunami came over the JR embarkment very much, so proverties behind the embarkment
were totally damaged. Moreover, from the damges
tresses, they reflect the JR underpass was the weakest
point, which suffer strongest impact during tsunami.

3B / Transects
through the Site

Approximate Scale

MIT Japan 3/11 Design Workshop / Summer 2011
Miyagi University / Keio University

WEST VALLEY | Utatsu (Minami-Sanriku, Miyagi)

TRANSECT [A] | JR EMBARKMENT ENLAGRED
3.11 Tsunami level (+18 m)

FRONT: Minor erosion happened, the gravel surface is slightly washed out.

3.11 Tsunami
45

BACK (VALLEY)oFRONT (RIVER)

2. JR Embarkment

Description(i.e. slopes, vegetation zones vs. urbanized, etc.)

Inventory along Transect

Ground (0 m)
Catchwater (- 1.8 m)

SECTION B

Site Analysis

BACK: Serious erosion happened, the embarkment surface is totally
washed out, the soil infill is exposed.

3B / Transects
through the Site

The JR embarkment has different extend in termof damages. At the front, the surface was slightly
washed out. At the back, serious soil erosion is happened to the embarkment.

Approximate Scale

MIT Japan 3/11 Design Workshop / Summer 2011
Miyagi University / Keio University

WEST VALLEY | Utatsu (Minami-Sanriku, Miyagi)

TRANSECT [B] | Kindergarten

Peak (+ 14 m)

3.11 Tsunami

3.11 Tsunami level (+ 5 m)
Platform (+ 4.5 m)

Kindergarten

Reservoir

Description(i.e. slopes, vegetation zones vs. urbanized, etc.)

Although the kindergarten is located at relatively
low altitude place, but due to its geographical condition of its context, it has minimal damage during
3.11 tsunami.

Inventory along Transect

Catchwater (- 1.5 m)

Site Analysis

3B / Transects
through the Site

From observation, the kindergarten is located in a smallvalley, which joins to the major west valley. And thekindergarten is built on top of a podium about four andhalf meters higher, it became potential protection during the tsunami.

Approximate Scale