Runoff characteristics of COD, BOD, C, N and P loadings from rivers to enclosed coastal seas

Inoue, Takanobu; Ebise, Senichi

doi:10.1016/0025-326x(91)90641-5

Cited by 29 publications

(14 citation statements)

References 1 publication

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“…In major rivers in Japan, it is generally recognized that most of the phosphorus runs off in the form of particulate rather than dissolved form during the high flow stages 2,12 , and most of the total annual load of the suspended matter occurs during the several days of flood-events in a year 14,16 . Consequently, continuous monitoring is essential to evaluate the importance of suspended matter load on nutrient runoff 4 .…”

Section: Introductionmentioning

confidence: 99%

Flood Event Loadings of Nitrogen and Phosphorus from the Yahagi River to Chita Bay, Japan

Tanaka¹,

Kodama²,

Sawada³

et al. 2009

JARQ

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A 4-year data set of continuous monitoring of suspended matter and nutrients concentration has been analyzed to evaluate the inter-annual variability and the effects of flood events on the sediment transport and nitrogen, phosphorus loadings from the Yahagi River to Chita Bay, Japan. Nitrogen was mainly loaded in dissolved form, which accounted for 59% to 88% of the annual loads, while phosphorus was mainly loaded in particulate form (45% to 78%). Loads of suspended matter and total phosphorus (T-P) by the historical flood event of the Tokai Heavy Rainfall accounted for 83% and 65% of the annual loads, respectively. Particulate phosphorus (PP) load by the Tokai Heavy Rainfall accounted for up to 1.1 to 3.2 times of the annual T-P load of the other years. Molar ratio of dissolved total nitrogen (DTN) load to dissolved total phosphorus (DTP) load during the observation period varied from 29.5 to 41.1, while the ratio of total nitrogen (T-N) load to T-P load was relatively lower (10.9 to 23.8). The concentrated load of suspended matter which occurs during flood events is found to have a great impact on the nutrients runoff to the coastal sea both in quality and quantity.

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Section: Introductionmentioning

confidence: 99%

Flood Event Loadings of Nitrogen and Phosphorus from the Yahagi River to Chita Bay, Japan

Tanaka¹,

Kodama²,

Sawada³

et al. 2009

JARQ

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“…Nutrient concentrations in rivers draining large watersheds dominated by farmland typically increase as water discharge increases (Inoue and Ebise 1991;House and Warwick 1998;Scanlon et al 2004). However, in the Takkobu River and Kushiro River, there was no clear correlation between water flow and nutrient concentration.…”

Section: Inflow Of Total Nitrogen and Total Phosphorusmentioning

confidence: 90%

Hydrology, suspended sediment dynamics and nutrient loading in Lake Takkobu, a degrading lake ecosystem in Kushiro Mire, northern Japan

Ahn

Nakamura

Mizugaki

2007

Environ Monit Assess

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Suspended sediment and nutrient loadings from agricultural watersheds have lead to habitat degradation in Lake Takkobu. To examine their relationships with land-use activities, we monitored sediment, nutrient and water discharges into the lake for a 1-year sampling period. The Takkobu River contributed the largest portion of the annual water discharge into the lake, compared with the other tributaries. During dry conditions, lake water flowed into the Kushiro River, and conversely during flooding, Kushiro River water flowed into the lake. Inflows from the Kushiro River had a high proportion of inorganic matter, with high concentrations of total nitrogen and total phosphorus, attributed to agricultural land-use development and stream channelization practiced since the 1960s in the Kushiro Mire. Nutrient loadings from these two rivers were significantly higher during flooding than in dry conditions. However, there was no clear correlation between river discharge and nutrient concentrations. Since land-use activities in the Kushiro River and Takkobu River watersheds were concentrated near rivers, nutrients easily entered the drainage system under low flow conditions. In contrast, water discharged from small, forest-dominated watersheds contained a low proportion of inorganic matter, and low nutrient concentrations. The suspended sediment delivered to the lake during the sample period was estimated as approximately 607 tons, while the total nitrogen and total phosphorus inflows were about 10,466 and 1,433 kg, respectively. Suspended sediment input into the lake was 65%, and total nitrogen and total phosphorus were 40% and 48%, respectively, being delivered by the Kushiro River.

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“…TP concentrations in the period of increasing of water discharge differed greatly from those in the period of their decreasing. During a rainfall event, the SS concentrations increase by more than one or two orders of magnitude compared with that on a normal day (e.g., Ebise and Inoue, 1991;Inoue and Ebise, 1991;Inoue et al, 2003;Yamada and Inoue, 2005). Observed concentrations of SS also increased at the peak of water discharge in the rainfall event (Fig.…”

Section: Phosphorus Loadmentioning

confidence: 99%

“…Daily nutrient loads from farmland can change not only seasonally and with anthropogenic activity, but also during rainfall events. Diffuse pollution loads from farmland can accelerate dramatically during even short rainfall events (e.g., Ebise and Inoue, 1991;Inoue and Ebise, 1991;Inoue et al, 2003), though observations and evaluation of water discharge and nutrient concentrations at these times are difficult. Loads from diffuse pollution sources cannot be calculated accurately by weekly research, which is normally researched at the time when the water discharge was almost same as the base flow.…”

Section: Estimations In 4 Cases Of Nutrient Loadsmentioning

confidence: 99%

Evaluation of Nutrient Loads from a Citrus Orchard in Japan

Tsushima

Koike

Horinouchi

et al. 2009

J. of Wat. & Envir. Tech.

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We estimated four methods of calculating loads of nutrients from a citrus orchard in Japan. River water discharge and nutrient loads were examined every week for 2 years and more intensively at the time of one rainfall event. River water level was recorded automatically at 5-minute intervals. Nutrient concentrations and water discharge data obtained for the load varied with the evaluation methods, because the estimations made during rain events differed. Nutrient loads calculated by the four methods ranged from 2004 kg/year to 4194 kg/year for total nitrogen and from 30.3 kg/year to 44.6 kg/year for total phosphorus from the watershed area of 78.3 ha with citrus orchard and forest. Particulate form nutrients from farmland were loaded by runoff during rainfall events, and nutrient load increased quickly more so with phosphorus than with nitrogen during rainfall events. There is thus a need to quantify the degree of nutrient load from farmland in rainfall events. Continuous observation data will be needed to obtain appropriate values for load from diffuse pollution sources.

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Runoff characteristics of COD, BOD, C, N and P loadings from rivers to enclosed coastal seas

Cited by 29 publications

References 1 publication

Flood Event Loadings of Nitrogen and Phosphorus from the Yahagi River to Chita Bay, Japan

Flood Event Loadings of Nitrogen and Phosphorus from the Yahagi River to Chita Bay, Japan

Hydrology, suspended sediment dynamics and nutrient loading in Lake Takkobu, a degrading lake ecosystem in Kushiro Mire, northern Japan

Evaluation of Nutrient Loads from a Citrus Orchard in Japan

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