SiteName

Irvine Nature Center

Coordinates

39°25′59″N 76°45′46″W

Study Area Map

# Figure 1: Map of Irivine Nature Center Sensor placement

Field Observations

Weather and Site Conditions

According to Weather Underground, the Westminster, Maryland weather station (located near the Westminster Radio Tower) recorded 0.00 inches of precipitation during the study period. No rainfall events were documented, indicating consistently dry conditions throughout data collection. The absence of precipitation likely contributed to stagnant stream flow, which also led to us finding a sensor completely dry.

Sensor Images

06/27/25 (Before)

# Figure 2: Initial Sensor images at Irvine Stream

09/02/25 (After)

# Figure 3: Sensor Images taken upon September 2nd, 2025
Sensor Site Conditions
  • Lower Sensor: Located in a shaded area with slow flow and stable banks reinforced by both tree roots and branches. The streambed was visible, and evidence suggested the stream had shifted slightly right, exposing sediment along the left bank.
  • Middle Sensor: The flow was extremely slow and the water appeared murky, indicating limited movement and possible sediment buildup from reduced velocity.
  • Upper Sensor: The stream-bed was completely dry upon arrival. The sensor rested on moist, muddy soil, likely holding water from previous rainfall events. It was situated on a downward slope stabilized by tree roots in the riparian zone. The sensor was relocated due to the absence of surface flow.
Bank Stability and Flow Summary

All sensor locations exhibited moderately to highly stable banks supported by dense riparian vegetation and steep slopes that formed a natural ravine. Overall, flow speed was extremely slow across the study area—fastest at the downstream (Lower) sensor and nonexistent at the Upper sensor.

Precipitation

no recorded precipitation during this time

# Figure 4: Temperature over time graph of the entire study period showing the temperature flux of all    four sensors.

# Figure 5: Mean daily temperatures recorded by the four iButton sensors (Upper Stream, Lower Stream, Air) across the study period. Values represent the average temperature for each sensor per day, illustrating overall thermal differences among sensor positions.
library(dplyr)
library(ggplot2)

# Load the data
summary_slopes <- read.csv("/Users/deneyo/Downloads/summary_slopes.csv")

irvine_filtered <- summary_slopes %>%
  filter(Site == "Irvine", Sensor != "Air")



# Stacked bar plot for Irvine only
ggplot(
  irvine_filtered,
  aes(x = Sensor, fill = wetness)
) +
  geom_bar(position = "stack") +
  scale_x_discrete(labels = c(
  "Lower" = "Downstream",
  "Middle" = "Middle Stream",
  "Upper" = "Upstream"
))

  labs(
    title = "Sensor Counts by Wetness (Irvine)",
    x = "Sensor",
    y = "Count",
    fill = "Wetness"
  ) +
  theme_minimal()
## NULL
# Figure 6: Sensor wetness count across the study period. Values represent the amount of days that each sensor was classified as wet. This graph excludes the air sensor.
Diurnal Temperature Slopes — August 15th (No Precipitation)
Sensor Min_Time Max_Time Next_Min_Time Min_Temp Max_Temp Slope_Up_C_per_hr Slope_Down_C_per_hr
Upstream 2025-08-15 06:30:01 2025-08-15 14:30:01 1755288901 66.442 71.848 0.676 -0.470
Middle Stream 2025-08-15 04:46:01 2025-08-15 14:16:01 1755292561 69.077 72.678 0.379 -0.129
Downstream 2025-08-15 05:12:01 2025-08-15 11:42:01 1755300421 68.092 82.494 2.216 -0.843
Air 2025-08-15 05:27:01 2025-08-15 14:27:01 1755300421 69.137 79.043 1.101 -0.600 

# Figure 7:. Hourly temperature changes across all four sensors during the morning–afternoon warming period on August 15th, 2025. The figure shows the rise in temperature as solar radiation increases through midday.
Cooling Slopes — August 1 (12 PM to 12 AM)
Sensor Start_Time End_Time Start_Temp End_Temp Cooling_Slope_F_per_hr
Upstream 2025-08-01 16:00:01 2025-08-01 23:45:01 67.343 65.540 -0.233
Middle Stream 2025-08-01 16:01:01 2025-08-01 23:46:01 69.077 67.275 -0.233
Downstream 2025-08-01 16:12:01 2025-08-01 23:57:01 70.794 65.390 -0.697
Air 2025-08-01 16:12:01 2025-08-01 23:57:01 70.939 65.532 -0.698 

# Figure 8: Hourly temperature changes across all four sensors during the afternoon–night cooling period on August 1st. The figure highlights the decline in temperature following sunset.

Analysis

The Irvine Nature Center stream has shown characteristics of an intermittent to ephemeral stream. Among all the monitored streams, Irvine exhibits the unique nature of groundwater influence at the upstream location. The Figure 6 plot shows that wetness increases as water travels toward the midstream sensor. However, a clear disconnectivity emerges between the midstream and downstream sensors. Both figures 4 and 5 display temperature and mean graphs, further showing that the downstream sensor remained consistently dry throughout the entire study period, as it mimics the air sensor. While upper reaches may maintain limited subsurface flow, the lack of sustained baseflow suggests that this is a losing stream. No recorded precipitation further proves that this stream struggles to flow without rain. Figures 7 and 8, which are close-ups of daily warming and cooling, show that the downstream sites exhibited larger diurnal temperature swings, reflecting a tendency to heat rapidly. While warming, the upstream and midstream temperatures are relatively lower, while both the air and downstream sensors increase past 1 degree per hour. Looking more closely, the downstream sensor shows a slope of 2.216 degrees, the highest of all sensors. A bigger case is that this sensor is directly affected by sunlight since the air sensor is shaded and warms at a 1.101 rate. A cause of this disconnectivity could be the permeable soils, which allow water to infiltrate quickly. With continued monitoring will see more if the stream is truly ephemeral or intermittent.