Journal of Japan Society on Water Environment

Original Paper

Improvement of Coastal Marine Sediments by Capping with Granulated Coal Ash

Shinya NAKAHARA, Kiyonori HIRAOKA, Tamiji YAMAMOTO, Hideki UESHIMA

Article type: Original Paper
2012 Volume 35 Issue 10 Pages 159-166
Published: 2012
Released on J-STAGE: October 10, 2012

DOIhttps://doi.org/10.2965/jswe.35.159

JOURNAL FREE ACCESS

Show abstractHide abstract

Our objective in this study is to evaluate the restoration effects of capping sediments in enclosed coastal seas with granulated coal ash (GCA). We investigated the nutrient and sulfide concentrations in the sediments pore water and overlying water as well as the number of individuals and species of benthos both in Ohko Fishing Port (short-term (84 days) experiments) and off Umashima Island (long-term (8 years) experiments) in the Seto Inland Sea. Significant decreases in DIN, DIP and sulfide concentrations in the sediments pore water were observed in Ohko Fishing Port, indicating the adsorption of DIN, DIP and sulfide onto GCA. Decreases in DIP and sulfide concentrations were also observed in the sediments pore water off Umashima.
Particularly, the increases in both the numbers of individuals and species of benthos in the latter case were significant, suggesting that bioturbation is also important for maintaining an aerobic sediment condition. A simple estimation implies that capping marine sediments with GCA could reduce the benthic flux of DIN and DIP at 98% even with short-term application.

View full abstract

Download PDF (1788K)

Note

Prediction of the Hypolimnetic Oxygen Deficit in the Reservoir

Shingo MASUKI, Morihiro AIZAKI, Katsuhiro SAKAMOTO

Article type: Note
2012 Volume 35 Issue 10 Pages 167-171
Published: 2012
Released on J-STAGE: October 10, 2012

DOIhttps://doi.org/10.2965/jswe.35.167

JOURNAL FREE ACCESS

Show abstractHide abstract

Investigation of the oxygen concentration distribution in hypolimnetic water was conducted in Sanbe reservoir. We calculated the areal hypolimnetic oxygen deficits (AHOD) from changes in the amount of oxygen by the field observation. In addition, we compared the measured AHOD with the predicted AHOD calculated by Cornett & Rigler's equation. In conclusion, the results indicate that the AHOD can be predicted with -2~0.5% errors (n=2) when the net phosphorus sedimentation velocity (v) was 14 m·y^-1. It is concluded that the AHOD can be predicted by Cornett & Rigler's equation in a reservoir with high water retention rate.

View full abstract

Download PDF (705K)

Survey Report

Horizontal Distribution of Peridinium spp. (Dinophyceae) Cysts in Surface Sediments from Sameura Dam and Tomisato Dam Reservoir in Winter

Koichiro MIZUSHIMA, Toshiyuki SASASE, Makoto TERAZAKI, Takashi NIIZAWA ...

Article type: Survey Report
2012 Volume 35 Issue 10 Pages 173-180
Published: 2012
Released on J-STAGE: October 10, 2012

DOIhttps://doi.org/10.2965/jswe.35.173

JOURNAL FREE ACCESS

Show abstractHide abstract

The horizontal distributions of Peridinium spp. cysts in surface sediments from the Sameura Dam and Tomisato Dam reservoirs in winter were determined to understand the mechanism of cyst deposition in this study. The cyst density downstream of the Seto River, which is an influent river of the Sameura Dam reservoir, was higher than those in the other sites (ex., Dam site). This higher cyst density downstream was probably caused by the extensive formation of cysts by motile cells and by sedimentation in the Seto River, determined on the basis of the dynamic pattern of Peridinium bipes and turbidity. In the Tomisato Dam reservoir, the cyst density of the reservoir intake formed at a low water level was higher than those in the other sites, which was considered to be caused by the deposition of cysts flowing that flowed down from upstream.

View full abstract

Download PDF (1177K)

Register with J-STAGE for free!