Water quality and spatial parameters from the main channel of a 6th order stream collected with an uncrewed surface vehicle

Nitrate concentrations in streams and rivers in the midwestern United States are often elevated, reflecting the predominance of agriculture in the surrounding landscape. Recent advances in technology, including surface-water drones and more precise sensors, provide an opportunity to investigate nitrate dynamics with high spatial and temporal resolution. We deployed an aquatic drone, the AquaBOT, in a 6th-order, agriculturally influenced river to examine longitudinal patterns in water quality. Our goal was to measure the spatial and temporal heterogeneity in nitrate and nitrate-removal processes and determine the influence of tributary inputs on mainstem chemistry. We navigated the drone along a 12-km reach of the Des Moines River (Iowa, USA) nine times between June 2021 and August 2022. Across the deployments, mean nitrate concentration was positively related to discharge and was nearly two orders of magnitude higher in spring than summer. We observed contrasting patterns in mainstem ni..., This dataset was collected along a 12.4-km reach of the Des Moines River, a 6th-order river in Central Iowa, USA. The study reach, located ~50 km northwest of the city of Des Moines, Iowa, begins at the upstream site (UP) near Boone, Iowa at 42°02'13.6\"N 93°55'39.8\"W and ends at the downstream site (DOWN) at 41°57'59.0\"N 93°53'47.0\"W. A surface-water drone equipped with water-quality sensors (the “AquaBOT”) measured longitudinal patterns in water chemistry along the 12.4-km reach of the Des Moines River. Nine AquaBOT runs were carried out in the spring through fall across two years (2021, 2022), , # AquaBot Manuscript Supporting Data

[https://doi.org/10.5061/dryad.np5hqc02x](https://doi.org/10.5061/dryad.np5hqc02x)

## Description of the data and file structure

This dataset contains water quality parameters (Water temperature, specific conductivity, dissolved oxygen, and nitrate-N) from sensors attached to an aquatic uncrewed surface vehicle (drone) within the main channel of our study reach as well as distance down stream calculated from the drones GPS coordinates. Each tab contains these main channel parameters for one of the 9 sampling dates. These data are essential for understanding the longitudinal patterns in nitrate and conductivity detailed in our research paper. 
### Files and variables

#### File: Mainstem\_AquaBOT\_Data\_Format.xlsx

**Description:** Water quality parameters for each sampling date. Main channel values only.

##### Variables

* TIMESTAMP: the date and time of each record. Each tab within the file is a separate date. 
* Water_Temp_deg C: Water tempera...,