Time dependence of sediment accretion rates: Short- and long-term variability in an urban tidal marsh

Understanding the temporal variability of sediment accretion is crucial for assessing the resilience of tidal marshes to accelerated sea-level rise, particularly in urban settings where sediment delivery and hydrology are frequently altered. This study investigates sediment accretion across multiple timescales in Tinicum Marsh, an urban tidal wetland in Philadelphia. Using event-scale sediment traps, annual SET-MH measurements, and decadal radioisotope dating, the research reveals that sediment accretion rates vary significantly with timescale, aligning with the Sadler Effect. Event-based rates were much higher than annual and decadal rates, especially during storms, which delivered more mineral-rich sediments. Accretion was influenced by elevation and distance from tidal channels, and substantial shallow subsidence was observed. Although current accretion exceeds long-term sea-level rise, it only marginally keeps up with recent rates, highlighting the need for multi-scale analysis to a..., , # Time dependence of sediment accretion rates: Short- and long-term variability in an urban tidal marsh

Dataset DOI: [10.5061/dryad.0vt4b8h9s](10.5061/dryad.0vt4b8h9s)

## Description of the data and file structure

### Files and variables

#### File: Event-Based_.csv

**Description:** This dataset contains event-based sediment deposition data collected from Tinicum Marsh, located in Philadelphia, PA. Sediment traps were deployed, and sediment deposition was measured following individual rainfall or tidal events to capture short-term sediment deposition across transects and plots. The dataset includes raw measurements (e.g., sediment dry weight) and calculated metrics such as the area of sediment trap filter (sq/m) and deposition rate (mm/yr), and was collected between 2011 and 2024

**Missing Values:** Field values in the data files of \"NA\" or \"-\" or blank fields (empty cells) should be treated as no data available.

##### Variables

* Batch/Project: Identifier for the collection batc...,