# A Web-Based Tool to Estimate Pollutant Loading Using LOADEST

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## Abstract

**:**

## 1. Introduction

_{0–6}are coefficients; Q is streamflow, dtime is decimal time; and per is the period defined by the user.

## 2. Materials and Methods

## 3. Application of LOADEST WEB

#### 3.1. Demonstration of USGS Data Retrievals and Input Error Checking

#### 3.2. Application for Average Annual Sediment Load Reduction

^{2}, with 74% (326 km

^{2}) of the watershed land use being agricultural area (Table 1). The LBC watershed area was 52 km

^{2}, with 90% (47 km

^{2}) of the watershed land use being urban area (Table 1). Streamflow and sediment data (‘Suspended sediment concentration, milligrams per liter’, USGS water quality parameter code: 80154) were retrieved from USGS server via web access by LOADEST WEB. Sediment data from 27 February 2007 to 7 December 2009 for USGS station 03351500 and sediment data from 6 January 2000 to 7 September 2004 for 03353637 with streamflow data from 1 January 2000 to 31 December 2013 were used to estimate average annual sediment loads. The water quality target was set to 80.0 mg/L [22]. Park and Engel [17] suggested to select the regression model numbered 3 in LOADEST for average annual sediment load estimations, since the regression model provided the most accurate and precise sediment load estimates. Therefore, the regression model 3 was selected for sediment load estimations. Daily sediment load predictions by LOADEST and observed data at USGS station 03351500 had Nash-Sutcliffe efficiency (NSE) of 0.84 and coefficient of determination (R

^{2}) of 0.88. And, NSE and R

^{2}at USGS station 03353637 were 0.51 and 0.97.

USGS Station | Watershed Name | Total Area (km^{2}) | Agriculture (km^{2}) | Urban (km^{2}) |
---|---|---|---|---|

03351500 | Fall Creek near Fortville, IN | 438 | 326 | 51 |

03353637 | Little Buck Creek near Indianapolis, IN | 52 | 3 | 47 |

^{9}kg/year (or 288.6 kg/ha/year), while target average annual sediment load (or allowable load) was 17.2 × 10

^{9}kg/year (or 391.8 kg/ha/year); therefore, the required reduction for the FCF watershed was 0.0% (Table 2). However, estimated average annual sediment load in the LBC watershed was 2.5 × 10

^{9}kg/year (or 487.3 kg/ha/year), while target average annual sediment load (or allowable load) was 1.8 × 10

^{9}kg/year (or 336.9 kg/ha/year); therefore, the required reduction for the LBC watershed was 30.9% (Table 2).

USGS Station | Water Quality Target | Estimated Load | Required Reduction | ||
---|---|---|---|---|---|

(10^{9} kg/year) | (kg/ha/year) | (10^{9} kg/year) | (kg/ha/year) | ||

03351500 | 17.2 | 391.8 | 12.6 | 288.6 | 0% |

03353637 | 1.8 | 336.9 | 2.5 | 487.3 | 31% |

## 4. Conclusions

## Acknowledgement

## Author Contributions

## Conflicts of Interest

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**MDPI and ACS Style**

Park, Y.S.; Engel, B.A.; Frankenberger, J.; Hwang, H.
A Web-Based Tool to Estimate Pollutant Loading Using LOADEST. *Water* **2015**, *7*, 4858-4868.
https://doi.org/10.3390/w7094858

**AMA Style**

Park YS, Engel BA, Frankenberger J, Hwang H.
A Web-Based Tool to Estimate Pollutant Loading Using LOADEST. *Water*. 2015; 7(9):4858-4868.
https://doi.org/10.3390/w7094858

**Chicago/Turabian Style**

Park, Youn Shik, Bernie A. Engel, Jane Frankenberger, and Hasun Hwang.
2015. "A Web-Based Tool to Estimate Pollutant Loading Using LOADEST" *Water* 7, no. 9: 4858-4868.
https://doi.org/10.3390/w7094858