 Water Quality Variability in a Bioswell and Concrete Drainage Pipe, Southwest Lincoln, Nebraska Jessica Shortino, B.S. University of Nebraska-Lincoln April 29, 2009

Introduction  Determine how effective bioswells are at minimizing the impacts of water runoff  Both an underground concrete lined drainage and a bioswell were sampled for certain water quality parameters  Contained both surface water and groundwater

Research Problem Objective Examine water quality variability over time Hypothesis If runoff is filtered through a bioswell, then we will expect to see better water quality

Review of Literature Bioswells Urban Runoff Water Quality for Wildlife Water Quality for Humans Why it’s Important

Study Site Bioswell Student Lots Practice Fields Drainage Ditch

Bioswell Site 1

Bioswell Site 2

Bioswell Site 3

Concrete Site 4

Testing Methods  Hydrolab  Dissolved Oxygen  pH  Water Temperature  Total Dissolved Solids  Specific Conductance  Samples taken 10 times from February 25,2009 to April 22, 2009

Testing Methods cont.  UNL Water Center  Total Organic Carbon  Chemical Oxygen Demand  Samples taken 5 times on:  March 4, March 25, April 8, April 10, and April 15, 2009  Alkalinity  Stream and Depth Measurements

 Results and Discussion

Ideal levels are above 5-6 ppm and range from 0-18 ppm Measurements higher at beginning of sampling -Over Saturation -Cold temperatures did not mean lower DO Controlled by: aquatic organisms, consumption of plants, water temperatures, flow, and depth April 10 th was sampled after a rain event DO

Impacts DO and rate of photosynthesis The highest average for the bioswell was site 1 -Paved Surfaces Impacts of higher water temperature in site 4 Bioswell did not impact water temperatures Water Temperature

Rainwater pH: 5.6 Neutral pH: 7 Wildlife: 4.5 to 9.5 pH is higher when there is less CO 2 Site 2 had largest pH ranges Bioswell did not impact pH greatly pH

Levels of mg/L will stabilize pH -Nebraska water is between mg/L Most readings between normal ranges Bioswell site 1 had most variability Sites containing groundwater had stable alkalinity readings Alkalinity

Depth Impacts: Water temperature and DO levels Average Depth of Sites: 1: 5.8 cm 2: 6.8 cm 3: 19 cm 4: 6.9 cm Width Impacts: Streamflow, TDS, and DO Site 3 had the most water, which was at end of bioswell Depth & Width

Sources: soil contamination, road salts, general stormwater runoff Bioswell site 1 had highest average Sites with slower flow decreased TDS Data incomplete since water not deep enough for probe TDS & Specific Conductance

Pristine:  S/cm Normal: 200-1,000  S/cm Saline: 1,000-10,000  S/cm Highly correlated to Total Dissolved Solid Bioswell sites within normal ranges Data incomplete since water not deep enough for probe Specific Conductance

Low readings towards end of sampling because increase in carbon in the water High organic contents means an increase in the growth of microorganisms COD < 5.0 for all samples except on March 4-low temperatures TOC is highly correlated with Total Dissolved Solids and Specific Conductance TOC & COD

Limitations  Data Incomplete  Initial survey of site  Compounded by dry season  Initially thought 4 th site was surface water runoff  Can’t make comparison  Eight week period  Potential for more sampling?

Conclusions  Bioswells can be an effective at protecting some water quality parameters that were tested  However, high readings at beginning of sampling

Conclusions cont. -Underground concrete pipe had more stable ranges -Bioswell needs to be maintained -Bioswell only had some saturated spots More concentrated pollution Bioswell Site 1 Duckweed at Concrete Site 4

Questions, Comments?