Water Quality Index Score: 62, Marginal
2014 was not a good year for the San Diego River. It dropped two levels on our Water Quality Index score, moving from Good in 2013 to Marginal in 2014, and giving it the dubious honors of being the only watershed to get worse. Key data takeaways include:
- Commonly high levels of phosphorus and ammonia
- Extremely low levels of dissolved oxygen more often than not
- Repeated reports from our volunteers noting excessive amounts of algae and duckweed
This is an excellent example to demonstrate how the region’s historic drought conditions impacted water quality in our inland waters last year. I grew up playing in the water at the old mission dam, which has one of our sampling sites nearby, and I can’t recall the water levels ever reaching the lows that we saw this year
All three bullet points in the San Diego Watershed data relate to one another and differently demonstrate high amounts of nutrients in the river. To say the least, this river is out of balance.
High nutrient levels, which often start as fertilizers on our lawns and gardens, cause algae and duckweed growth, which ultimately deplete oxygen levels and kill marine life. We think the low water levels contributed to slower flows and warmer waters, creating the perfect breeding ground for explosive algae growth in the San Diego River. And greatly impacting water quality.