Estimation of Hydraulic Parameters of Coastal Aquifers Using Tidal Response Method with Frequency Decomposition Techniques Optimized for Predominant Tides

DOI JASI Web Site 1 Citations

Bibliographic Information

Other Title
  • 卓越潮汐に合わせ最適化した周波数分離法を組み合わせた潮汐応答法による沿岸域帯水層の水理定数推定
  • 卓越潮汐に合わせ最適化した周波数分離法を組み合わせた潮汐応答法による沿岸域帯水層の水理定数推定 : 多良間島の147日地下水位データへの適用
  • タクエツ チョウセキ ニ アワセ サイテキカ シタ シュウハスウ ブンリホウ オ クミアワセタ チョウセキ オウトウホウ ニ ヨル エンガンイキ タイスイソウ ノ スイリ テイスウ スイテイ : タリョウ カントウ ノ 147ニチ チカ スイイ データ エ ノ テキヨウ
  • ―Application to 147-day groundwater-level data from Tarama Island―
  • ―多良間島の147日地下水位データへの適用―

Search this article

Abstract

<p>The tidal response method of analyzing responses of groundwater levels to the tide for estimating aquifer hydraulic parameters was applied to an unconfined coastal aquifer on Tarama Island, Okinawa Prefecture, in order to investigate aquifers beneath wide areas of the island. The method was combined with isolation of specified tidal oscillations by digital filtering and discrete Fourier transform. The length of the used groundwater-level observation data was set based on an appropriate length for the discrete Fourier transform to isolate predominant tidal components, 3,279 hours (about 137 days), and additionally required 10 days for employing prior digital filtering. Estimated hydraulic diffusivities for aquifers beneath several investigation lines in coastal areas of Tarama Island were 4 to 15 m2·s-1. Hydraulic conductivities estimated therefrom were in the order of magnitude of 10-2 m·s-1, the same as the result of a pumping test previously reported. Several coastal parts of the aquifer vary three- to four-fold in estimated diffusivities and conductivities, with smaller values for the northern part and the smallest for the north-northwestern part of the aquifer. This also is consistent with the freshwater-lens distribution biased toward similar directionality.</p>

Journal

Citations (1)*help

See more

Related Projects

See more

Keywords

Details 詳細情報について

Report a problem

Back to top