Datasets:

NTU-CompHydroMet-Lab
/

mataian-moses-stac

The list below outlines the corresponding experimental procedures and the specific physical units used as column headers or data keys in Mataian_Sediment_Data.[csv / xlsx / json].

1. Sampling & Geospatial Information

Field	Description
`Sample_ID`	Unique alphanumeric identifier for each sampling site.
`Date_and_time`	Timestamp of field sampling (YYYY-MM-DD HH:MM:SS).
`Sampler`	Name of the personnel who collected the sample.
`WGS84_Lat`	Latitude in the WGS84 coordinate system (Decimal Degrees).
`WGS84_Lon`	Longitude in the WGS84 coordinate system (Decimal Degrees).
`twd97_E`	Easting in the TWD97 (Taiwan Datum 1997) projected coordinate system (m).
`twd97_N`	Northing in the TWD97 projected coordinate system (m).

2. Bulk Sample Preparation & Field Moisture

Field	Description
`Bulk_Dish_g`	Weight of the empty container (W1) used for the bulk soil sample (g).
`Bulk_Wet_Soil_Dish_g`	Weight of the container plus the wet bulk soil (W2) immediately retrieved from the field (g).
`Bulk_AirDry_Soil_Dish_g`	Weight of the container plus the bulk soil (W3) after prolonged laboratory air-drying preparation (g).
`Bulk_Apparent_Moisture_pct`	Apparent field moisture content (w), calculated prior to sieving: `[(W2 - W3) / (W3 - W1)] × 100` (%).

3. Specific Gravity & Hydrometer Calibration

Field	Description
`Specific_Gravity_Gs`	Specific gravity of soil solids (Gs), measured via pycnometer or assigned based on spatial proximity.
`Hydro_Sample_AirDry_g`	Weight of the air-dried fine soil fraction prepared for the hydrometer sedimentation test (g).
`Hygro_Dish_g`	Weight of the empty weighing bottle used for hygroscopic moisture determination (g).
`Hygro_Wet_Soil_Dish_g`	Weight of the weighing bottle plus air-dried fine soil before oven-drying (g).
`Hygro_Dry_Soil_Dish_g`	Weight of the weighing bottle plus absolute dry soil (g).
`Air_Dry_Moisture_pct`	Hygroscopic moisture content of the air-dried fines (%).
`Hydro_Absolute_Dry_Soil_g`	Absolute oven-dry mass of the soil used in the hydrometer test (Ws), corrected as: `[Air-dry mass / (1 + Hygroscopic moisture)]` (g).

4. Sedimentation (Hydrometer) & Sieve Analysis

Field	Description
`Hydro_Time_min`	Array of elapsed observation times during the hydrometer test (min).
`Hydro_Reading`	Array of uncorrected hydrometer readings (R) corresponding to the elapsed times.
`Hydro_Temp_C`	Array of suspension temperatures recorded at each hydrometer reading (°C).
`Sieve_Opening_mm`	Array of standard sieve opening sizes used in the mechanical sieve analysis for coarse fractions (mm).
`Sieve_Retained_g`	Array of the mass of dry soil retained on each respective standard sieve (g).

5. Particle Size Fractions (by Diameter D)

Field	Description
`Gravel_pct_75_to_4_75mm`	Percentage of Gravel (75 mm > D ≥ 4.75 mm, retained on No.4 sieve) (%).
`Coarse_Sand_pct_...`	Percentage of Coarse Sand (4.75 mm > D ≥ 2.0 mm) (%).
`Medium_Sand_pct_...`	Percentage of Medium Sand (2.0 mm > D ≥ 0.425 mm) (%).
`Fine_Sand_pct_...`	Percentage of Fine Sand (0.425 mm > D ≥ 0.075 mm) (%).
`Silt_pct_0_075_to_...`	Percentage of Silt (0.075 mm > D ≥ 0.005 mm, passing No.200 sieve) (%).
`Clay_pct_lt_0_005mm`	Percentage of Clay (D < 0.005 mm) (%).

6. Gradation Curve & Index Properties

Field	Description
`Curve_Size_mm`	Array of merged particle diameters (D) derived from both sieve and hydrometer analyses (mm).
`Curve_Passing_pct`	Array of cumulative percent passing corresponding to each particle diameter (%).
`D60_mm`	Particle diameter at 60% passing (D60) (mm).
`D50_mm`	Median particle diameter (D50) at 50% passing (mm).
`D30_mm`	Particle diameter at 30% passing (D30) (mm).
`D10_mm`	Effective particle diameter (D10) at 10% passing (mm).
`Cu`	Coefficient of Uniformity (Cu = D60 / D10), evaluating the gradation spread.
`Cc`	Coefficient of Curvature [Cc = (D30²) / (D10 × D60)], evaluating the gradation symmetry.

Dataset Notes

1. Unmeasured Values

Values recorded as -1 within the arrays indicate that the specific measurement was skipped, unmeasured, or deemed inapplicable for that particular sample.

2. Suspended Sediment Samples

Samples M5g and M5h represent suspended sediment samples collected directly from the river using water bottles. Therefore, they follow a different collection protocol compared to standard bed material samples.

3. Specific Gravity (Gs) Assignments

Actual specific gravity measurements (using a pycnometer) were only conducted on representative samples M1, M3a, and M5a. Assuming that nearby sediments share similar physical properties, these measured Specific_Gravity_Gs values were assigned to adjacent samples based on spatial proximity as follows:

Measured Sample	Assigned to
M1	5, 6A, 6B, 6C, M1, M2
M3a	1, 2, 3, 4, M3a, M3b, M3c, M4
M5a	M5a, M5b, M5c, M5d, M5e, M5f, M5g, M5h