April-26-2001
A lake analysis was performed on April-26 (2001) by Mac McCune of Lake Management Services, Inc (Richmond, TX, tel 281 342 6018). Below is his summary:
Overall, the lake is in pretty good condition and there are no apparent concerns with water quality. However, residents should be aware that conditions may change depending on primary purpose(s), weather, seasons and lack of awareness. It is important to remember that we typically don't become concerned with things we don't know much about and this complacency can lead to procrastination in recognizing and solving problems that may occur naturally in nature but are generally not conducive to urbanization.
With the design of the lake, the significant depths and limited access, solving a major problem(s) could become an expense the Home Owner Association has not likely encountered in the past and probably is not prepared to address. This can be offset by making residents aware of the significance of this impoundment in relation to the overall development.
Crystal Lake is typically in the middle stages of eutrophication. This is a term meaning the natural aging process of a body of water leading to its eventual extinction as a swamp. While this process may take a hundred years in the rural sector, urbanization tends to accelerate the eutrophic process by increasing both organic and inorganic loading. Nature has a pre-chartered course planned for this impoundment. Unfortunately, this course is generally not conducive to urbanization. It is important for residents to understand that Crystal lake is a living aquatic ecosystem governed by nature but influenced by man and not a swimming pool.
Here is his water analysis:
August-31-2002
Water was collected at depths of 0.5 meter, 1.0 meter, and 2.0 meters, approximately in the middle of the lake and also in the south east corner. Analyses were performed using kits obtained from Petsmart to qualitatively measure ammonia, nitrate, nitrite, phosphate, and dissolved oxygen. The phosphate test was modified to be able to measure the developing blue color spectrophotometrically, and thus get a more quantitative result using external standards.
- ammonia: less than 1 mg/Liter
- nitrate: less than 5 mg/Liter
- nitrite: less than 0.1 mg/Liter
- oxygen: saturated, about 8 mg/Liter (difficult to measure)
- pH: more than 7, less than 8 (7.7 +- 0.2 was the average reading after 30 min stabilization. Difficult to measure reliably due most likely to low buffer capacity of the lake.)
- phosphate: less than 0.1 mg/Liter (see standard curve below)
The black data points are from external standards, and the purple data points are values obtained from samples of Crystal Lake.
- transparency measured with a Secchi Disk
- turbidity measured as absorbance at 260 and 280 nm against distilled water (August 31, 2002):
| location | 260 nm | 280 nm |
| 0.5 m Center | 0.193 | 0.172 |
| 1.0 m Center | 0.209 | 0.186 |
| 2.0 m Center | 0.197 | 0.176 |
| 0.5 m SEast | 0.211 | 0.186 |
| 1.0 m SEast | 0.200 | 0.179 |
| 2.0 m SEast | 0.203 | 0.179 |
Conclusion:
The EPA water quality criteria state that phosphates should not exceed 0.05 mg/l if streams discharge into lakes or reservoirs, 0.025 mg/l within a lake or reservoir, and 0.1 mg/l in streams or flowing waters not discharging into lakes or reservoirs to control algae growth (USEPA, 1986). Surface waters that are maintained at 0.01 to 0.03 mg/l of total phosphorus tend to remain uncontaminated by algae blooms. Crystal Lake is thus just at the limit, and is slightly eutrophic. The measurements (less than 6.5 feet) with the Secchi disk also indicate an eutrophic state of Crystal Lake. Green murky water is a reflection of such eutrophic conditions.
Layman's Guide for Measuring A Lake's Trophic State
Home News Homes for Sale Deed Restrictions Pearland Useful Numbers Lake Stuff Homepages
web@grooveyart.com