Golf Course Management

OCT 2017

Golf Course Management magazine is dedicated to advancing the golf course superintendent profession and helping GCSAA members achieve career success.

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72 GOLF COURSE MANAGEMENT 10.17 for comparison with sites downstream of the areas influenced by golf course management practices. Water quality samples and measure - ments were collected four to six times per year. In-stream physical indicators of water quality that were measured included temper - ature, pH and dissolved oxygen. These were measured with a calibrated multi-parameter probe (Hydrolab Quanta; Loveland, Colo.) at inflow and outflow sites at each course. The maximum temperature for non-impaired, non-tidal Virginia Piedmont waters is 90 F. Healthy dissolved-oxygen levels are listed as > 4.0 mg/liter for non-tidal waters in the coastal and Piedmont zones. Water pH for healthy streams ranges from 6.0 to 9.0 (6). Samples for chemical indicators of water quality were taken consistently at the same locations and within 6 inches (15.24 cm) of the surface in areas of predominate flow. They were analyzed using a SEAL AutoAnalyzer III and standard methods: G-109-94 (nitrate- nitrogen), G-102-93 (ammonium-nitrogen) and G-103-93 (phosphate-phosphorus) (1). Mean concentrations of nitrate-nitrogen, am - monium-nitrogen and phosphate-phosphorus were calculated from each of the sample sites separately. Differences between the upstream and downstream locations were calculated by subtracting mean downstream nutrient con - centrations from mean upstream nutrient con- centrations for each stream. Differences were used to decrease the effect of autocorrelation within repeated measures so that the samples could be treated as independent statistical units (E.P. Smith, Virginia Tech Department of Statistics, personal communication). In cases where an outflow was connected to mul - tiple inflows, data were analyzed by averaging the means of the multiple inflow streams. To test for significance, the calculated differences between inflow and outflow locations were compared with zero. Virginia golf course superintendents were surveyed online to assess management levels and adoption of BMPs on their golf courses. Seventy golf courses — representing 42 Vir - ginia counties within the bay watershed — re- turned completed surveys. Results ysical indicators The temperature criterion was not exceeded for the non-tidal Piedmont waters except for one instance (92 F) at the outflow location of Course 1 during the summer of 2011. Water pH of the streams was rarely outside the accept - able range of 6.0 to 9.0. Exceptions were sea- sonal but temporary, with pH readings of 5.0 to 6.0 or 9.0 to 10.0 in less than 10% of the measurements across three years of monitoring. Dissolved-oxygen levels were occasionally below established criteria for healthy aquatic life (4.0 mg/liter), but low levels were mostly associated with low baseflow (low-water flow) of these small streams in summer or early fall (see Figure 2 for an example of seasonal varia - tion on Course 6). With sufficient rainfall or with runoff in cooler seasons, dissolved- oxygen concentrations were adequate for healthy aquatic life and did not differ signifi - cantly between inflow and outflow locations. If any of these physical parameters had re - mained consistently worse at outflow locations relative to inflow locations, they would have served as indicators that golf course manage - ment practices were contributing to sediment or nutrient pollution. Our data indicate that this was not the case. C mical indicators Nitrate-nitrogen. Nitrate-nitrogen concen - trations were generally low or below detection limits at all golf course sites (Figure 3). Statis - tical analysis generally did not reveal signifi- cant differences between inflow and outflow locations. For example, three years of sam - pling revealed no inflow to outflow nitrate- nitrogen concentration differences on courses 1, 2, 3, 4, 7 and 9. One of the exceptions in nitrate-nitrogen concentrations was stream B on Course 5, which had greater nitrate-nitrogen leaving the course (4 mg/liter) than entering (1 mg/liter). This stream flowed through an underground pipe on the course, and we had no way to de - termine the cause of elevated nitrate. Interest- ingly, phosphate-phosphorus levels were not elevated in the outflow of this underground stream (Figure 4). Course 6 nitrate-nitrogen levels were also higher at outflow (3 mg/liter) than at inflow (1.5 mg/liter). Finally, stream B on Course 8 had higher inflow nitrate-nitro - gen (2 mg/liter) relative to the outflow con- centration (0.2 mg/liter). Dissolved oxygen (mg/liter) Course 5-8IN Course 5-4OUT Dissolved oxygen levels Figure 2. Seasonal dissolved-oxygen levels (mg/liter) on Course 5 at stream inlet and outlet points over four years.

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