1992 Fiscal Year Final Research Report Summary
Changes of the hydrologic cycle due to urbanization
| Project/Area Number |
03452304
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
自然地理学
|
|---|
| Research Institution | University of Tsukuba |
|---|
Principal Investigator |
KAYANE Isamu Univ. Tsukuba Geoscience Professor, 地球科学系, 教授 (10015539)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
SHIMADA Jun Univ. Tsukuba Geoscience Asst. Professor, 地球科学系, 講師 (80206169)
TANAKA Tadashi Univ. Tsukuba Geoscience Asoc. Professor, 地球科学系, 助教授 (50015880)
|
|---|
| Project Period (FY) |
1991 – 1992
|
| Keywords | Urban hydrology / Groundwater flow / Hydraulic potential / Discharge mechanism / Spring type |
|---|
| Research Abstract |
1) Classification of springs in Tokyo was made. Jindaiji spring as the cliff type and Zenpukuji spring as the valley head type were selected as typical ones for analysis of recharge mechanism. Obtained results are: (1)Cliff type springs discharge at the outcrop of Musashino gravel layer. (2)Its recharge areas are of the order of 10^5-10^6 m^2 extending upstream direction to 200-2000 m. (3)Valley head type springs has dried out due to decline of the water table in the Musashino gravel layer. (4)To recover valley head type springs the water table have to be increased by ca. 2 m. 2) Changes of the regional groundwater flow pattern in three-dimensional space were made clear by constructing the distribution map of the hydraulic head on two-dimensional vertical cross-section for years 1970, 1980, and 1987. Data used are the water level of observation wells, well logs with a single screen, and the static water level of wells for municipal water supply. From the revealed pattern of regional groundwater flow, roles of Tama and Sayama hills and the Tama River as groundwater recharage source, the function of Tachikawa fault in preventing groundwater flow, and areal differences in response of the aquifer aquitard system to regulation and prohibition against goundwater with drawal are made clear. 3) In order to measure the hydraulic potential in borehole, a double packered groundwater pressure measuring instrument was developed. Measured data are stored in the attached field data logger, which can operate for one day without electricity. The field test in borehole in granite proved the instrument to be useful. The instrument can also used for measuring the hydraulic conductivity of the rock.
|
