Our group has studied the spatiotemporal variation of soil and water salinity in an artificial salt marsh along the Arakawa River estuary and developed a practical model for predicting soil salinity. The salinity of the salt marsh and the water level of a nearby channel were measured once a month for 13 consecutive months. The vertical profile of the soil salinity in the salt marsh was measured once monthly over the same period. A numerical flow simulation adopting the shallow water model faithfully reproduced the salinity variation in the salt marsh. Further, we developed a soil salinity model to estimate the soil salinity in a salt marsh in Arakawa River. The vertical distribution of the soil salinity in the salt marsh was uniform and changed at almost the same time. The hydraulic conductivity of the soil, moreover, was high. The uniform distribution of salinity and high hydraulic conductivity could be explained by the vertical and horizontal transport of salinity through channels burrowed in the soil by organisms. By combining the shallow water model and the soil salinity model, the soil salinity of the salt marsh was well reproduced. The above results suggest that a stable brackish ecotone can be created in an artificial salt marsh using our numerical model as a design tool.

中文翻译：

---

荒川河口盐沼土壤盐度预测实用模型的开发

我们小组研究了荒川河口人工盐沼中土壤和水盐度的时空变化，并开发了预测土壤盐度的实用模型。连续 13 个月每月测量一次盐沼的盐度和附近河道的水位。在同一时期每月测量一次盐沼中土壤盐度的垂直剖面。采用浅水模型的数值流模拟忠实地再现了盐沼中的盐度变化。此外，我们开发了一个土壤盐度模型来估计荒川河盐沼中的土壤盐度。盐沼土壤盐分的垂直分布是均匀的，几乎同时发生变化。此外，土壤的导水率很高。盐分的均匀分布和高水力传导率可以通过盐分通过生物在土壤中挖洞的通道的垂直和水平输送来解释。通过结合浅水模型和土壤盐度模型，盐沼土壤盐度得到了很好的再现。上述结果表明，使用我们的数值模型作为设计工具，可以在人工盐沼中创建一个稳定的微咸交错带。