Attribution of phosphorus load in various watersheds in Illinois

The state of Illinois is one of the largest contributors of nutrient loads to the Mississippi-Atchafalaya River Basin (MARB). The purpose of this study is to understand phosphorus trends in the Illinois River Basin (IRB) and its sub-watersheds and to analyze the attribution of the trend. The total phosphorus (TP) flux in IRB at Valley City increased from 1995 to 2019 with a rate of +8472 kg P yr-1. This study suggests dissolved phosphorus (DP) load from point sources in the Sangamon River Basin, the increase of streamflow, and the legacy phosphorus in Lower IRB as reasons for the increasing TP load trend in the IRB. Regional TP yield trend of Sangamon River Basin (SRB) and Upper Sangamon River Basin (USRB) showed increasing trends with rates of 2.62 kg km-2 yr-1 and 1.39 kg km-2 yr-1. The potential impact of legacy phosphorus was insignificant on the overall TP yield trend in SRB. Phosphorus from the Sanitary District of Decatur (SDD) was critical in increasing TP yield in SRB. The rise in the number of industrial facilities and the change in industrial processes for soybean biorefinery seemed to be related to the increase in TP load in SRB at Oakford. The increased conservation reserve program (CRP) appeared to be related to the reduction in TSS and PP yield. The increase in CRP and the significant decrease in manure application due to a substantial reduction in livestock inventory likely resulted in a TP load decrease in Indian Creek. In recent years, the increase in precipitation might have resulted in a slight increase in TP load. The impact of BMPs on TP load was also evaluated with the SWAT model. The mixed application of filter strip and winter cover crop showed the highest efficiency in terms of TP load reduction among the BMP scenarios tested.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Agricultural & Biological Engr

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2023

Author dc:creator

• Kim, Daniel Chulgi

Contributors dc:contributor

• Bhattarai, Rabin
• Kalita, Prasanta Kumar
• McIsaac, Gregory F
• Markus, Momcilo

• Mann-kendall Test
• Seasonal Kendall Test
• Regional Kendall Test
• Trend Analysis
• Illinois River Basin
• Sangamon River Basin
• Indian Creek
• Phosphorus
• The Soil And Water Assessment Tool (swat)
• Best Management Practices (bmps)

Statement dc:rights

• Copyright 2023 Daniel Kim

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/121210

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F121210