Water Quality

Monitoring Water Quality

The quality of water in Planning District 16 is monitored, along with the rest of the Commonwealth, by Virginia’s Department of Environmental Quality (DEQ). DEQ’s Integrated Report to the United State’s Environmental Protection Agency (EPA) documents 5 categories of water quality. Level 1 being healthy and level 5 being so impaired that it requires remedial action by law. Per DEQ:

“This biennial report satisfies the requirements of the U.S. Clean Water Act sections 305(b) and 303(d) and the Virginia Water Quality Monitoring, Information and Restoration Act. The goals of Virginia’s water quality assessment program are to determine whether waters meet water quality standards, and to establish a schedule to restore waters with impaired water quality.”

The 2022 Integrated Report

This report revealed that the state does not have sufficient data on majority of rivers and their tributaries (~87%) in our region to make a determination on health. With limited time and resources, there are more waterways in Virginia than staff have hours in the day to collect data. However, only 7.16% of lakes and reservoirs are uncategorized due to insufficient data. This is likely because this region contains fewer lakes and reservoirs than rivers and streams.

 For this region, we condensed the numerical categories and subcategories from EPA into 5 standards:

  • Level 1: Healthy
  • Level 2: Mostly Healthy
  • Level 3: Insufficient Data
  • Level 4: Mildly Impaired
  • Level 5: Heavily Impaired

To read the full EPA categorization, read the Assessment Methodology from DEQ.

Combined River and Lake Data

Looking at the combined percentages of each category, insufficient data is still the largest category with 47%. On the left, you can see the distribution of water quality monitoring stations in our region. Even still, most of our waterways (mostly rivers) are not being monitored. Let’s dive deeper and look at the data for rivers and lake separately without the insufficient data category. Click the next symbol to see these charts.



If you remove the insufficient data category, then more than half (87%) of RIVERS are impaired in our region. A water body that does not meet water quality standards will not support one or more of its designated uses. Such waters have “impaired” water quality. In most cases, a cleanup plan (called a Total Maximum Daily Load) must be developed and implemented to restore impaired waters. The distinguishing factor between heavily and mildly impaired is the requirement that heavily impaired (category 5) waterways havea TMDL. 

Lakes and Resevoirs

When we remove the insufficient data category, it is easier to see that majority of our lakes and reservoirs (85%) are heavily impaired. This emerging trend is mirrored across the state where the Integrated report shows that statewide 86% of lakes are impaired. In 2020, only 80% were impaired. Additionally, statewide, only 16% of rivers and 75% of estuaries are impaired. These numbers were stable statewide from 2020 to 2022– making lakes the only category to increase in that time period statewide.

To the Left: the statewide comparison of impaired vs. unimpaired waterways in the different categories (Lakes, Rivers, and Estuaries).

Key Takeaways

The combined dataset also obscures one more takeaway: river data is mostly insufficient, but lakes data is not.

Most lakes are categorized while most rivers are not. Why? Perhaps because we have less lakes or that DEQ does not the monitor most headwaters. The DEQ Integrated Report Summary reports that 65% of Virginia’s rivers are headwater systems, and are not monitored by DEQ’s ambient water quality network. Additionally, 80% of state rivers were not able to be classified. This mirrors what we see in Planning District 16.

Quick Facts

1. This region struggles with bacterial contamination (80.6% of impaired rivers had E. coli as a cause). This is mirrored in the state where bacteria is the #1 pollutant (see page 22 of DEQ Integrated Report Summary– chart to right)

2. Most of our lakes and reservoirs are severely impaired, and it’s getting worse. DEQ’s 2022 data shows that most of the impairment in lakes in our regions comes from Polychlorinated biphenyls, or PCBs (61.11%). The source of these PCBs is listed as “unknown.”

3. Most of our rivers have insufficiently data to be categorized, yet only a small portion of lakes are unclassified. 



The biggest takeaway from this analysis of DEQ’s 2022 Integrated Report data in Planning District 16 is that we don’t understand most of what is causing impairment to our rivers and lakes. This can be further clarified that as: (1) lakes where we do have sufficient data to classify, we do not understand the sources of pollutions and (2) in majority of rivers, we do not have sufficient data to classify. Those rivers we can classify are mostly polluted with E. coli (bacteria). Compared to the statewide analysis, trends in our regions mirror the rest of the Commonwealth for both lakes and rivers.